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BrainyCalculators is a free, independent reference library of more than 358 online calculators covering the topics people search for every day. Whether you are planning your finances, monitoring your health, solving a maths problem, running a business, designing an engineering project, estimating your tax bill, or making an everyday decision, you will find a purpose-built tool here β with no account, no subscription, and no fees.
Our Finance calculators cover the full lifecycle of personal and business money management: EMI and loan repayments, SIP and lump-sum investment projections, compound interest, ROI analysis, mortgage affordability, and retirement planning. Each tool uses the standard formula adopted by financial institutions and regulators so you can trust the numbers.
The Health & Fitness section includes clinically validated tools for BMI, BMR, TDEE, body fat percentage, calorie requirements, heart rate zones, and hydration. Formulas are sourced from peer-reviewed journals and bodies such as the WHO and NIH. Results always carry the reminder that they are informational estimates β your healthcare provider remains the right person for medical decisions.
For Maths, Statistics, and Engineering, BrainyCalculators offers everything from basic percentage and fraction arithmetic through to standard deviation, probability distributions, unit conversions, electrical calculations, and civil engineering estimators. These are practical tools for students, professionals, and anyone who needs a quick, reliable answer without opening a spreadsheet.
Our Business, Tax, and HR calculators help founders, accountants, and operations teams with profit margin analysis, GST and VAT breakdowns, payroll estimates, employee turnover costs, and more. The Daily Life and Conversion tools cover the practical questions that come up every week: fuel costs, tip splitting, age calculation, date differences, and unit conversions across length, weight, temperature, and speed.
Every calculator on this site is built to the same standard: an industry-recognised formula, cross-validated results, transparent methodology, and a plain-English explanation of what is being calculated and why. Use the category tabs below to jump straight to the tools you need, or scroll through to explore the full library.
How We Build Our Calculators
Industry-Standard Formulas
Every tool uses the accepted formula from the relevant professional body β financial regulators, WHO, NIST, IEC β not a custom approximation.
Regularly Updated
Tax rates, clinical guidelines, and engineering standards change. We review and update calculators on a weekly schedule and whenever a standard is revised.
Cross-Validated Results
Before publication, each calculator is checked against official reference tools and published tables to confirm accuracy across a range of inputs.
Transparent Methodology
Every calculator page shows the formula used, a worked example, and source references so you can verify results independently.
Mobile-Friendly Design
All calculators are fully responsive and tested on phones and tablets. Inputs update results instantly with no page reload needed.
Privacy by Design
Calculations run entirely in your browser. No input data is sent to our servers, stored, or shared with third parties.
For full details see our Calculator Methodology and Editorial Policy.
Finance Calculators
ROI, EMI, mortgage, compound interest & more.
ROI Calculator
Calculate return on investment and measure the profitability of any investment.
EMI Calculator
Calculate your monthly EMI for home, car, or personal loans instantly.
Mortgage Calculator
Estimate monthly mortgage payments including principal, interest, taxes, and insurance.
Compound Interest Calculator
See how your investments grow over time with the power of compounding.
SIP Calculator
Calculate returns on your Systematic Investment Plan (SIP) investments.
Loan Calculator
Calculate monthly payments, total interest, and amortization schedule for any loan.
Simple Interest Calculator
Calculate simple interest on any principal amount, rate, and time period.
SWP Calculator
Calculate how long your corpus lasts with a Systematic Withdrawal Plan.
Retirement Calculator
Plan your retirement by calculating how much you need to save each month.
Personal Loan Calculator
Calculate monthly payments, total interest, and amortization for personal loans.
Car Loan Calculator
Calculate your monthly car loan payment, total interest, and payoff schedule.
Home Loan Calculator
Calculate monthly home loan EMI, total interest payable, and repayment schedule.
Credit Card Payoff Calculator
Calculate how long it takes to pay off your credit card balance and total interest paid.
Debt Payoff Calculator
Calculate a debt payoff plan using avalanche or snowball method.
Refinance Calculator
Calculate potential savings when refinancing your mortgage or auto loan.
Savings Calculator
Calculate how much your savings will grow with regular deposits and compound interest.
Inflation Calculator
Calculate the real value of money over time accounting for inflation rate.
Investment Return Calculator
Calculate total return, CAGR, and inflation-adjusted return on any investment.
Future Value Calculator
Calculate the future value of a lump sum or regular investment at a given rate.
Present Value Calculator
Calculate the present value of a future sum of money using a discount rate.
Net Worth Calculator
Calculate your total net worth by adding assets and subtracting liabilities.
FIRE Calculator
Calculate your FIRE number and years to financial independence using the 4% rule.
APY Calculator
Calculate Annual Percentage Yield (APY) from nominal interest rate and compounding frequency.
APR Calculator
Calculate Annual Percentage Rate (APR) including fees to find the true cost of a loan.
Dividend Yield Calculator
Calculate dividend yield, annual dividend income, and dividend payout ratio.
Stock Average Calculator
Calculate average cost per share when buying stocks at different prices.
Cryptocurrency Profit Calculator
Calculate profit, loss, and ROI on cryptocurrency trades including fees.
Forex Profit Calculator
Calculate profit or loss in pips and currency for forex trades.
Trading Risk Calculator
Calculate risk per trade, risk-reward ratio, and expected value of trades.
Position Size Calculator
Calculate the correct position size based on account size, risk percentage, and stop loss.
Margin Calculator
Calculate margin required, leverage, and margin level for trading positions.
Profit & Loss Calculator
Calculate profit or loss on any trade including entry price, exit price, and fees.
Debt-to-Income Ratio Calculator
Calculate your debt-to-income ratio to assess loan eligibility.
Rent vs Buy Calculator
Compare renting vs buying a home over time to find the best financial option.
Emergency Fund Calculator
Calculate how much you need in your emergency fund based on expenses and months.
Savings Goal Calculator
Calculate how long it takes to reach a savings goal or how much to save monthly.
Financial Independence Calculator
Calculate your FI number and years to financial independence using the 4% rule.
Dollar Cost Averaging Calculator
Calculate total investment, average cost per share, and returns using DCA strategy.
Dividend Reinvestment Calculator
Calculate portfolio growth with dividend reinvestment (DRIP) over time.
Bond Yield Calculator
Calculate current yield, yield to maturity, and yield to call for bonds.
Real Rate of Return Calculator
Calculate the real rate of return on investments adjusted for inflation.
Risk Reward Ratio Calculator
Calculate the risk/reward ratio for trades, investments, and financial decisions.
CAGR Calculator
Calculate the compound annual growth rate of an investment over any period.
Lump Sum Investment Calculator
Calculate the future value of a one-time lump sum investment with compound interest.
Understanding Finance Calculations
Finance calculators help you make sense of the numbers behind everyday money decisions. Four concepts sit at the core of most financial planning: EMI (Equated Monthly Instalment), SIP (Systematic Investment Plan), ROI (Return on Investment), and Compound Interest.
An EMI splits a loan into equal monthly payments covering both principal and interest. The standard formula used by banks factors in the loan amount, annual interest rate, and repayment tenure β so even a small rate change has a surprisingly large effect on total interest paid over the life of a loan. Use our EMI calculator before committing to any mortgage or personal loan to see exactly what each scenario costs.
SIP calculators project the future value of regular investments β for example, a fixed monthly contribution to a mutual fund. Because returns are reinvested each period, growth is exponential rather than linear: time in the market matters far more than the size of each contribution, especially over horizons of ten years or more.
ROI measures the efficiency of an investment as a simple percentage: net profit divided by initial cost, multiplied by 100. It cuts through marketing claims and lets you compare fundamentally different opportunities on a level playing field. Compound interest, meanwhile, is what makes long-term investing powerful β interest earned in one period itself earns interest in the next, accelerating growth without additional effort on your part.
Business Calculators
Profit margin, GST, discount & business tools.
GST Calculator
Calculate GST inclusive and exclusive amounts for any tax rate instantly.
Profit Margin Calculator
Calculate gross and net profit margins for your products and services.
Discount Calculator
Calculate the final price after discount, or find the original price.
Break-even Calculator
Calculate break-even point in units and revenue for any product or business.
VAT Calculator
Add or remove VAT from any price. Calculate VAT amount and net/gross price instantly.
Sales Tax Calculator
Calculate sales tax amount and total price for any US state or custom tax rate.
Markup Calculator
Calculate selling price, markup percentage, or cost price for any product.
Commission Calculator
Calculate sales commission earnings for flat rate, tiered, and split commission structures.
Revenue Calculator
Calculate total revenue, average revenue per unit, and revenue growth rate.
Inventory Calculator
Calculate inventory value, reorder point, economic order quantity (EOQ), and stock turnover.
Salary Calculator
Convert salary between hourly, daily, weekly, monthly, and yearly amounts.
Overtime Calculator
Calculate overtime pay for weekly, daily, or double-time overtime rates.
Payroll Calculator
Calculate employee net pay after federal tax, state tax, Social Security, and Medicare deductions.
Invoice Calculator
Create and calculate invoices with line items, tax, discount, and due date.
Freelance Rate Calculator
Calculate your minimum freelance hourly rate based on desired income, expenses, and billable hours.
Hourly Wage Calculator
Calculate hourly wage from salary, or convert hourly pay to annual, monthly, and weekly income.
Business Loan Calculator
Calculate monthly repayment, total interest, and amortization schedule for a business loan.
Cash Flow Calculator
Calculate net cash flow, operating cash flow, and free cash flow from income and expenses.
Startup Cost Calculator
Estimate total startup costs including one-time setup costs and monthly operating expenses.
Employee Cost Calculator
Calculate the true total cost of hiring an employee including salary, benefits, taxes, and overhead.
ROAS Calculator
Calculate Return on Ad Spend (ROAS) to measure advertising campaign profitability.
CAC Calculator
Calculate Customer Acquisition Cost (CAC) from your total marketing and sales spend.
Customer Lifetime Value Calculator
Calculate CLV/LTV to understand long-term revenue per customer.
Churn Rate Calculator
Calculate customer churn rate, retention rate, and revenue churn for your business.
Conversion Rate Calculator
Calculate conversion rate, conversions needed, and revenue impact of rate changes.
CPM Calculator
Calculate CPM (Cost Per Mille) for advertising campaigns and media buys.
CPC Calculator
Calculate Cost Per Click (CPC) for PPC and digital advertising campaigns.
CPA Calculator
Calculate Cost Per Acquisition (CPA) for marketing campaigns and ad spend.
Ecommerce Profit Calculator
Calculate net profit, margin, and ROI for ecommerce products after all fees and costs.
Shopify Fee Calculator
Calculate Shopify transaction fees, payment processing costs, and net profit per sale.
Amazon FBA Calculator
Calculate Amazon FBA fees, net profit, and ROI for any product listing.
Etsy Fee Calculator
Calculate Etsy listing, transaction, and payment processing fees and net profit.
eBay Fee Calculator
Calculate eBay final value fees, PayPal fees, and net profit for any listing.
Return Rate Calculator
Calculate product return rate, cost of returns, and impact on net revenue.
Inventory Turnover Calculator
Calculate inventory turnover ratio, days inventory outstanding, and stock efficiency.
Business Calculations That Matter
Running a business involves dozens of routine calculations that, done manually, take time and introduce errors. Our business calculators automate the most important ones so you can focus on decisions rather than arithmetic.
Profit margin calculators help you understand how much of each pound or dollar of revenue actually flows through to profit. Gross margin strips out direct costs such as materials and labour. Net margin accounts for overheads, tax, and interest too. Knowing both is essential for pricing decisions β a product with a healthy gross margin can still destroy value if it carries too much overhead allocation.
GST and VAT calculators handle the most common compliance arithmetic: adding tax to a net price to get the gross total, or working backwards from a gross price to recover the tax component. These are especially useful at invoice time and during quarterly filings when mistakes can trigger penalties.
Discount and mark-up calculators let buyers and sellers quickly check whether a proposed price achieves the required margin, while break-even calculators show the minimum revenue needed to cover fixed and variable costs at a given price point β an essential planning tool when launching a new product or service.
Math Calculators
Percentage, algebra, geometry & arithmetic.
Percentage Calculator
Calculate percentages, percentage change, and percentage of a number easily.
Fraction Calculator
Add, subtract, multiply, and divide fractions. Simplify fractions and convert to decimals.
Scientific Calculator
Full-featured scientific calculator with trigonometry, logarithms, and advanced math functions.
Algebra Calculator
Solve algebraic expressions and evaluate equations step by step.
Equation Solver
Solve linear and quadratic equations for x step by step.
Quadratic Formula Calculator
Solve quadratic equations axΒ² + bx + c = 0 using the quadratic formula.
Matrix Calculator
Add, subtract, multiply matrices and calculate determinant and transpose.
Exponent Calculator
Calculate exponents, powers, and scientific notation instantly.
Logarithm Calculator
Calculate log base 10, natural log (ln), log base 2, and any custom base.
Root Calculator
Calculate square root, cube root, and nth root of any number.
Polynomial Calculator
Add, subtract, and multiply polynomials. Evaluate polynomials at given values.
Trigonometry Calculator
Calculate sin, cos, tan, and their inverses in degrees or radians.
Geometry Calculator
Calculate area, perimeter, volume and other properties of geometric shapes.
Area Calculator
Calculate the area of any shape β circle, triangle, rectangle, trapezoid, and more.
Volume Calculator
Calculate the volume of 3D shapes β cube, sphere, cylinder, cone, and more.
Perimeter Calculator
Calculate the perimeter or circumference of any shape easily.
Circle Calculator
Calculate the area, circumference, diameter, and radius of any circle.
Triangle Calculator
Calculate the area, perimeter, angles, and sides of any triangle.
Pythagorean Theorem Calculator
Calculate the missing side of a right triangle using the Pythagorean theorem.
Slope Calculator
Calculate slope, y-intercept, angle, and line equation from two points.
Distance Calculator
Calculate the distance between two points using the distance formula.
Prime Number Calculator
Check if a number is prime and find prime numbers up to any limit.
Factor Calculator
Find all factors and prime factors of any positive integer.
LCM Calculator
Calculate the Least Common Multiple (LCM) of two or more numbers.
GCF Calculator
Calculate the Greatest Common Factor (GCF/GCD) of two or more numbers.
Decimal to Fraction Calculator
Convert any decimal number to a simplified fraction instantly.
Fraction to Decimal Calculator
Convert any fraction to a decimal, including repeating and terminating decimals.
Scientific Notation Calculator
Convert numbers to and from scientific notation and perform arithmetic in scientific notation.
Mean Absolute Deviation Calculator
Calculate Mean Absolute Deviation (MAD) for any data set.
Sequence Calculator
Identify and calculate terms of number sequences including arithmetic, geometric, and Fibonacci.
Arithmetic Sequence Calculator
Calculate any term, sum, or common difference of an arithmetic sequence.
Geometric Sequence Calculator
Calculate any term, sum, or common ratio of a geometric sequence.
Binomial Theorem Calculator
Expand binomial expressions using the binomial theorem with full step-by-step solution.
Derivative Calculator
Calculate derivatives of common functions using differentiation rules.
Integral Calculator
Calculate definite and indefinite integrals of common functions.
Limits Calculator
Calculate limits of functions as x approaches a value using limit rules.
Making Sense of Maths Tools
Mathematics underpins almost every other discipline on this site β from interest rate calculations to engineering tolerances to health risk scores. Our maths calculators are designed to give you an instant, reliable answer while also showing you the working so you understand how that answer was reached.
Percentage calculators are among the most-used tools on the site because the concept appears in so many contexts: discounts, VAT, mark-ups, exam grades, growth rates, and more. Rather than guessing or rounding in your head, a percentage calculator eliminates arithmetic errors in seconds. Similarly, fraction and ratio calculators are invaluable when scaling recipes, mixing solutions, or comparing proportions in data.
Geometry and area calculators use exact formulas for standard shapes β triangles, circles, rectangles, trapezoids, spheres, and cones β meaning results are precise regardless of how unusual the dimensions are. For algebra, our tools can solve linear equations, simplify expressions, and evaluate polynomial functions, which is particularly useful for students checking their own workings or professionals who need a quick sanity check.
All maths calculators display the formula alongside the result so you can verify the method independently and adapt it to your own spreadsheets or code.
Statistics Calculators
Mean, standard deviation, probability & more.
Standard Deviation Calculator
Calculate mean, variance, and standard deviation for any data set.
Mean Calculator
Calculate arithmetic mean, geometric mean, and harmonic mean for any data set.
Median Calculator
Find the median (middle value) of any data set, sorted and unsorted.
Mode Calculator
Find the mode (most frequent value) of any data set, including multimodal sets.
Variance Calculator
Calculate population and sample variance for any data set.
Probability Calculator
Calculate basic probability, combined events, and conditional probability.
Z-score Calculator
Calculate z-score (standard score) and find corresponding probabilities.
Percentile Calculator
Calculate percentile rank and find the value at any percentile in a data set.
Sample Size Calculator
Calculate the required sample size for surveys and statistical studies.
Correlation Calculator
Calculate Pearson correlation coefficient between two variables.
Regression Calculator
Calculate linear regression equation, slope, and intercept for any data set.
Confidence Interval Calculator
Calculate confidence intervals for means and proportions.
Permutation Calculator
Calculate the number of permutations P(n,r) β ordered arrangements.
Combination Calculator
Calculate the number of combinations C(n,r) β unordered selections.
Binomial Distribution Calculator
Calculate binomial probability P(X=k), cumulative probabilities, mean, and variance.
T-Test Calculator
Perform one-sample, two-sample, and paired t-tests with p-value and confidence interval.
Chi Square Calculator
Calculate chi-square test statistic, p-value, and degrees of freedom for goodness of fit and independence tests.
Normal Distribution Calculator
Calculate probabilities and percentiles for the normal (Gaussian) distribution.
Poisson Distribution Calculator
Calculate Poisson distribution probabilities for events occurring at a known rate.
Geometric Distribution Calculator
Calculate geometric distribution probabilities for the number of trials until first success.
ANOVA Calculator
Perform one-way ANOVA test to compare means across multiple groups.
Covariance Calculator
Calculate sample and population covariance and correlation coefficient between two datasets.
Relative Risk Calculator
Calculate relative risk (risk ratio) from a 2Γ2 contingency table.
Odds Ratio Calculator
Calculate odds ratio and confidence interval from a 2Γ2 contingency table.
Margin of Error Calculator
Calculate the margin of error for survey results given sample size and confidence level.
Health Calculators
BMI, calorie, heart rate & fitness calculators.
BMI Calculator
Calculate your Body Mass Index (BMI) and find out your weight category.
Calorie Calculator
Calculate your daily calorie needs based on age, gender, height, weight, and activity level.
BMR Calculator
Calculate your Basal Metabolic Rate β the calories your body burns at rest.
Body Fat Calculator
Calculate your body fat percentage using the US Navy method or BMI method.
Water Intake Calculator
Calculate your daily water intake needs based on weight, activity, and climate.
Protein Intake Calculator
Calculate your daily protein needs based on weight, activity level, and fitness goal.
Pregnancy Calculator
Calculate your due date, conception date, and pregnancy milestones.
Ovulation Calculator
Calculate your ovulation date and fertile window based on your cycle.
Ideal Weight Calculator
Calculate your ideal body weight range based on height, gender, and frame size.
Heart Rate Calculator
Calculate your maximum heart rate and target heart rate zones for exercise.
Blood Alcohol Calculator
Estimate your Blood Alcohol Content (BAC) based on drinks, weight, and time.
Macro Calculator
Calculate your daily macronutrient targets β protein, carbs, and fat β for your goal.
TDEE Calculator
Calculate your Total Daily Energy Expenditure β how many calories you burn per day.
Lean Body Mass Calculator
Calculate your lean body mass β total weight minus body fat.
Calories Burned Calculator
Calculate calories burned during exercise based on activity, weight, and duration.
Waist to Hip Ratio Calculator
Calculate your waist-to-hip ratio and health risk category.
Waist to Height Ratio Calculator
Calculate your waist-to-height ratio, a strong predictor of cardiovascular disease risk.
Healthy Weight Range Calculator
Find your healthy weight range based on height, age, gender, and BMI.
Target Heart Rate Calculator
Calculate your target heart rate zones for fat burning, cardio, and peak performance.
Pregnancy Weight Gain Calculator
Calculate recommended pregnancy weight gain by trimester based on pre-pregnancy BMI.
Due Date Calculator
Calculate your estimated due date from last menstrual period or conception date.
Baby Growth Percentile Calculator
Calculate baby height and weight percentile based on WHO and CDC growth charts.
Body Shape Calculator
Determine your body shape (apple, pear, hourglass, rectangle) from your measurements.
Intermittent Fasting Calculator
Calculate your eating and fasting windows for 16:8, 18:6, 5:2, and other IF protocols.
Ideal Calorie Deficit Calculator
Calculate your ideal calorie deficit for safe, sustainable weight loss.
One Rep Max Calculator
Estimate your one-rep maximum (1RM) from weight lifted and reps using multiple proven formulas.
Running Pace Calculator
Calculate your running pace, speed, or finish time for any distance including 5K, 10K, half marathon, and marathon.
Cycling Speed Calculator
Calculate average cycling speed, distance covered, or time taken for any ride.
Body Surface Area Calculator
Calculate body surface area (BSA) using Du Bois, Mosteller, and Haycock formulas for medical and fitness use.
VO2 Max Calculator
Estimate your VO2 Max (maximal oxygen uptake) from heart rate, Cooper test, or Rockport walk test results.
Steps to Calories Calculator
Convert daily steps into calories burned based on your weight, height, and walking pace.
Workout Calories Calculator
Calculate total calories burned in a full workout session by adding multiple exercises with individual durations.
Using Health Calculators Responsibly
Health and fitness calculators can be powerful tools for self-awareness and goal-setting β but it is important to understand what they measure and what they do not. Every health calculator on BrainyCalculators uses formulas from peer-reviewed clinical research and standards set by bodies such as the World Health Organization and the National Institutes of Health.
BMI (Body Mass Index) is the most widely recognised screening tool for healthy weight ranges. It is calculated from height and weight alone, which makes it quick and universally applicable, but it does not distinguish between muscle and fat mass. Athletes can have a high BMI despite very low body fat. For a more complete picture, combine BMI with a body fat percentage or waist-to-height ratio measurement.
BMR (Basal Metabolic Rate) estimates the calories your body needs at rest β the baseline before physical activity is added. Multiply your BMR by an activity factor to get TDEE (Total Daily Energy Expenditure), which is the figure most useful for weight management. These are population-level estimates: individual metabolism varies, and results should be treated as a starting point rather than a precise prescription.
Heart rate, hydration, and calorie calculators follow the same principle: they provide evidence-based reference ranges to inform your decisions. Always consult a qualified healthcare professional before making changes to your diet, exercise, or medical care based on any calculator result.
Engineering Calculators
Unit conversion, electrical, civil & more.
Density Calculator
Calculate density, mass, or volume using the density formula D = M/V.
Pipe Weight Calculator
Calculate the weight of steel, PVC, or other pipe by outer diameter, thickness, and length.
Concrete Calculator
Estimate concrete volume and bags needed for slabs, footings, columns, and walls.
Steel Weight Calculator
Calculate the weight of steel bars, plates, pipes, and sections by dimensions.
Voltage Calculator
Calculate voltage using Ohm's Law (V = IR) or power equations (V = P/I).
Ohm's Law Calculator
Calculate voltage, current, resistance, or power using Ohm's Law and Watt's Law.
Watt Calculator
Calculate electrical power in watts from voltage and current, or resistance and voltage.
Resistance Calculator
Calculate total resistance for series and parallel resistor circuits.
Power Consumption Calculator
Estimate electricity cost by entering device wattage, usage hours, and electricity rate.
Fuel Consumption Calculator
Calculate fuel consumption rate, total fuel used, and fuel efficiency in L/100km or MPG.
Speed Calculator
Calculate speed, distance, or time using the formula Speed = Distance / Time.
Force Calculator
Calculate force, mass, or acceleration using Newton's Second Law (F = ma).
Torque Calculator
Calculate torque from force and lever arm length, or convert between torque units.
Pressure Calculator
Calculate pressure from force and area, or convert between pressure units.
Area Conversion Calculator
Convert between area units: sq meters, sq feet, acres, hectares, sq km, and more.
Unit Conversion Calculator
Convert between length, weight, temperature, volume, speed, and other units.
Material Cost Calculator
Estimate total material cost for construction or manufacturing projects by quantity and unit price.
Load Calculator
Calculate structural loads including dead load, live load, and total load per unit area.
Asphalt Calculator
Calculate the amount and cost of asphalt needed for driveways, roads, and parking lots.
Brick Calculator
Calculate the number of bricks needed for any wall with mortar joints.
Cement Calculator
Calculate the amount of cement bags, sand, and gravel needed for concrete or mortar mixes.
Tile Calculator
Calculate the number of tiles needed for any floor or wall area with grout lines and waste.
Flooring Calculator
Calculate flooring material needed for any room with waste factor and cost estimate.
Paint Calculator
Calculate the number of paint cans or litres needed to paint any room or surface.
Solar Panel Calculator
Calculate how many solar panels you need, estimated energy output, and payback period.
Battery Life Calculator
Calculate battery life, runtime, and capacity needed for any device or system.
Voltage Drop Calculator
Calculate voltage drop across cables and wires for electrical systems.
Cable Size Calculator
Calculate the correct cable size (cross-section area) for electrical installations.
Water Tank Calculator
Calculate water tank volume, capacity, and required size for household or commercial use.
Excavation Calculator
Calculate excavation volume, cut and fill quantities, and earthwork cost estimates.
Gravel Calculator
Calculate how much gravel, crushed stone, or fill material you need for any project.
Roofing Calculator
Calculate roofing materials, shingles, and cost for any roof pitch and area.
Stair Calculator
Calculate stair rise, run, number of steps, and stringer length for any total rise.
Beam Deflection Calculator
Calculate beam deflection and bending stress for simply supported and cantilever beams.
Daily Life Calculators
Age, date, fuel cost, tip & everyday tools.
Age Calculator
Calculate your exact age in years, months, days, hours, and minutes.
Fuel Cost Calculator
Calculate fuel cost for any trip based on distance, mileage, and fuel price.
Date Difference Calculator
Find the exact difference between two dates in days, weeks, months, and years.
Tip Calculator
Calculate tip amount, total bill, and split between any number of people instantly.
Time Zone Calculator
Convert time between any two time zones instantly with current DST support.
Currency Converter
Convert between 30+ world currencies with up-to-date exchange rates.
Time Calculator
Add or subtract time values, convert between time units, and calculate duration between two times.
Travel Budget Calculator
Plan your travel budget by estimating costs for flights, hotels, food, transport, and activities.
Sleep Calculator
Find the best bedtime or wake-up time based on 90-minute sleep cycles for optimal rest.
Love Calculator
Calculate love compatibility between two people based on names for fun.
Countdown Calculator
Calculate the exact number of days, hours, minutes, and seconds until any future event.
GPA Calculator
Calculate your GPA on a 4.0, 5.0, or 10.0 scale from your grades and credit hours.
Grade Calculator
Calculate your final grade from assignments and tests using weighted averages.
Random Number Generator
Generate random numbers within any range, or pick random items from a list.
Password Generator
Generate strong, secure random passwords with custom length and character options.
Unit Converter
Quickly convert everyday units: length, weight, temperature, volume, and speed.
BMI by Age Calculator
Calculate BMI adjusted for age and gender with healthy weight range recommendations.
Birthday Countdown Calculator
Find out exactly how many days, hours, and minutes until your next birthday or any special date.
Reading Time Calculator
Calculate how long it takes to read any text or book based on word count and reading speed.
Words Per Minute Calculator
Calculate your typing or reading words per minute (WPM) speed.
Text Length Calculator
Count characters, words, sentences, and paragraphs in any text instantly.
Screen Time Calculator
Calculate daily screen time, weekly total, and the impact on sleep and productivity.
Commute Cost Calculator
Calculate the annual and monthly cost of your daily commute including fuel, tolls, and time.
Meeting Cost Calculator
Calculate the real cost of a meeting based on number of attendees, salary, and duration.
Wedding Budget Calculator
Plan your wedding budget by category including venue, catering, photography, and flowers.
Party Budget Calculator
Plan and calculate the total budget for any party or event by number of guests and categories.
Shopping Discount Calculator
Calculate the final price after multiple discounts, tax, and cashback on any purchase.
Restaurant Split Bill Calculator
Split a restaurant bill evenly or by item, including tip and tax per person.
Pet Age Calculator
Convert your pet's age to human years for dogs, cats, rabbits, and other animals.
Pregnancy Week Calculator
Calculate your current pregnancy week and trimester from your due date or last period.
Life Expectancy Calculator
Estimate your life expectancy based on lifestyle, health habits, and demographic factors.
School Age Calculator
Calculate when a child starts school based on their birthday and local cutoff rules.
Anniversary Calculator
Calculate your anniversary date, days together, and upcoming milestones.
Real Estate Calculators
Property tax, rental yield, mortgage & affordability calculators.
Property Tax Calculator
Calculate your annual and monthly property tax based on assessed home value and local tax rate.
Rental Yield Calculator
Calculate gross and net rental yield on investment properties to evaluate rental income performance.
Rent Affordability Calculator
Find out how much rent you can afford based on your monthly income and expenses.
House Affordability Calculator
Calculate how much house you can afford based on your income, debts, and down payment.
Down Payment Calculator
Calculate the required down payment for a home purchase and see how different percentages affect your mortgage.
Mortgage Refinance Calculator
Calculate potential savings from refinancing your mortgage with a new interest rate and loan term.
Education Calculators
GPA, CGPA, attendance, study time & grade calculators.
CGPA Calculator
Calculate your Cumulative GPA (CGPA) from multiple semesters of course grades and credit hours.
Percentage to GPA Calculator
Convert your percentage marks to GPA on 4.0, 5.0, and 10.0 scales used by universities worldwide.
Study Time Calculator
Plan your study schedule by calculating how many hours to study per subject based on exam dates and difficulty.
Attendance Calculator
Calculate your current attendance percentage and find out how many classes you can miss or must attend to meet the minimum requirement.
Exam Score Calculator
Calculate your exam score, percentage, and grade from marks obtained out of total marks.
Conversion Calculators
Length, weight, temperature, speed & unit converters.
Length Converter
Convert between all length and distance units: meters, feet, inches, miles, kilometers, centimeters, and more.
Weight Converter
Convert between weight and mass units: kilograms, pounds, grams, ounces, tons, and more.
Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin, and Rankine temperature scales instantly.
Speed Converter
Convert between speed units: km/h, mph, m/s, knots, Mach, and more.
Volume Converter
Convert between volume units: liters, gallons, milliliters, cups, fluid ounces, cubic meters, and more.
Area Converter
Convert between area units: square meters, square feet, acres, hectares, square kilometers, and more.
Pressure Converter
Convert between pressure units: Pascal, bar, psi, atm, mmHg, and more.
Data Storage Converter
Convert between digital storage units: bytes, KB, MB, GB, TB, PB, and their binary equivalents.
AI & Tech Calculators
AI token cost, API pricing, SaaS metrics & cloud cost calculators.
AI Token Calculator
Calculate token count and cost for AI language model API calls.
OpenAI Cost Calculator
Calculate and compare costs across all OpenAI GPT models for your usage.
Claude Cost Calculator
Calculate monthly API costs for Anthropic Claude models based on your usage.
API Pricing Calculator
Compare and calculate monthly costs across multiple AI and cloud APIs.
SaaS MRR Calculator
Calculate Monthly Recurring Revenue (MRR) including new, expansion, contraction, and churned MRR.
SaaS ARR Calculator
Calculate Annual Recurring Revenue (ARR) from MRR, contracts, and growth metrics.
Startup Runway Calculator
Calculate how many months of runway your startup has based on cash and burn rate.
Burn Rate Calculator
Calculate gross and net burn rate and months of runway for startups.
Cloud Cost Calculator
Estimate and compare monthly cloud infrastructure costs across AWS, GCP, and Azure.
Storage Cost Calculator
Calculate cloud and local storage costs for files, databases, and media.
Internet Speed Calculator
Calculate download/upload time, speed in all units, and data transfer equivalents.
File Size Calculator
Convert file sizes between bytes, KB, MB, GB, TB and calculate storage requirements.
Bandwidth Calculator
Calculate required bandwidth for streaming, video conferencing, and data transfer needs.
Dev Tools Calculators
UUID generator, JSON formatter, Base64, regex tester & developer utilities.
UUID Generator
Generate v1, v4, and v5 UUIDs instantly in the browser.
QR Code Generator
Generate QR codes for URLs, text, contact cards, and Wi-Fi credentials.
Random Picker
Pick random items from any list β names, options, or custom entries.
Dice Roller
Roll any number and type of dice β d4, d6, d8, d10, d12, d20, and custom.
Coin Flip Simulator
Flip a coin, flip multiple coins, and track heads/tails statistics.
JSON Formatter
Format, validate, minify, and convert JSON to YAML or CSV.
Base64 Encoder/Decoder
Encode and decode text or files to and from Base64 instantly.
URL Encoder/Decoder
Encode and decode URLs, query strings, and special characters.
Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa.
Regex Tester
Test, debug, and build regular expressions with live match highlighting.
Color Converter
Convert colors between HEX, RGB, HSL, HSV, CMYK, and CSS formats.
Binary Converter
Convert numbers between binary, decimal, octal, and hexadecimal.
Hex Converter
Convert between hexadecimal, decimal, binary, and text (ASCII/UTF-8).
Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from any text.
Tax Calculators
Income tax, capital gains, payroll tax & refund calculators.
Income Tax Calculator
Estimate your income tax liability based on taxable income and filing status.
Capital Gains Tax Calculator
Calculate short-term and long-term capital gains tax on investments and property.
Payroll Tax Calculator
Calculate payroll taxes including Social Security, Medicare, and federal withholding.
Self-Employment Tax Calculator
Calculate self-employment tax (SE tax) for freelancers, contractors, and sole proprietors.
Corporate Tax Calculator
Calculate corporate income tax liability based on taxable income and applicable rates.
Tax Refund Calculator
Estimate your tax refund or amount owed based on income, deductions, and withholding.
Tax Withholding Calculator
Calculate the correct federal tax withholding from each paycheck based on W-4 information.
Property Transfer Tax Calculator
Calculate property transfer tax when buying or selling real estate.
Inheritance Tax Calculator
Estimate inheritance tax on assets received from an estate based on your state and relationship.
Estate Tax Calculator
Calculate federal and state estate tax on the value of a deceased person's taxable estate.
Insurance Calculators
Life, health, auto, home & disability insurance calculators.
Life Insurance Calculator
Calculate how much life insurance coverage you need based on income, debts, and dependents.
Term Insurance Calculator
Estimate term life insurance premiums based on age, health, coverage amount, and term length.
Disability Insurance Calculator
Calculate how much disability insurance income protection you need if you cannot work.
Health Insurance Cost Calculator
Estimate your annual health insurance cost including premiums, deductibles, and out-of-pocket expenses.
Auto Insurance Calculator
Estimate auto insurance premiums based on vehicle, driver profile, and coverage levels.
Home Insurance Calculator
Estimate homeowners insurance premiums based on home value, location, and coverage.
Insurance Needs Calculator
Assess your total insurance needs across life, health, auto, home, and disability coverage.
Insurance Premium Calculator
Calculate monthly and annual insurance premiums and compare coverage costs.
Construction Calculators
Rebar, drywall, paver, deck, fence & landscape material calculators.
Rebar Calculator
Calculate the amount and weight of rebar needed for concrete slabs, footings, and walls.
Drywall Calculator
Calculate drywall sheets, screws, joint compound, and tape needed for any room.
Paver Calculator
Calculate the number of pavers and base material needed for a patio, driveway, or walkway.
Deck Calculator
Calculate lumber, fasteners, concrete, and cost for building a deck.
Fence Calculator
Calculate fence posts, rails, boards, and material cost for any fence project.
Foundation Calculator
Calculate concrete, rebar, and formwork for slab, stem wall, and basement foundations.
Landscape Material Calculator
Calculate mulch, topsoil, gravel, and sand needed for any landscaping project.
Mulch Calculator
Calculate how many cubic yards or bags of mulch you need for garden beds.
Topsoil Calculator
Calculate how much topsoil you need for a garden, lawn, or raised bed.
Cubic Yard Calculator
Convert measurements to cubic yards for concrete, gravel, mulch, and any bulk material.
Manufacturing Calculators
OEE, cycle time, production capacity & scrap rate calculators.
Cycle Time Calculator
Calculate cycle time, takt time, and throughput for manufacturing processes.
OEE Calculator
Calculate Overall Equipment Effectiveness (OEE) from availability, performance, and quality.
Production Capacity Calculator
Calculate maximum production capacity based on machines, shifts, and cycle time.
Machine Utilization Calculator
Calculate machine utilization rate, idle time, and capacity efficiency.
Scrap Rate Calculator
Calculate scrap rate, first pass yield, and cost of poor quality.
Yield Calculator
Calculate production yield, rolled throughput yield, and first pass yield.
Downtime Calculator
Calculate production downtime, cost of downtime, and availability rate.
Production Cost Calculator
Calculate total production cost per unit including materials, labor, and overhead.
HR Calculators
Employee turnover, PTO, severance pay & productivity calculators.
Employee Turnover Calculator
Calculate employee turnover rate and cost of turnover for your organization.
PTO Calculator
Calculate PTO balance, accrual, and payout value for employees.
Vacation Accrual Calculator
Calculate vacation days accrued per pay period, month, and year.
Notice Period Calculator
Calculate the notice period required and last working day based on resignation date.
Severance Pay Calculator
Calculate severance pay based on years of service, salary, and company policy.
Attrition Rate Calculator
Calculate employee attrition rate by month, quarter, and year.
Employee Productivity Calculator
Calculate employee productivity, revenue per employee, and output per labor hour.
Logistics Calculators
Freight, shipping volume, pallet, dimensional weight & delivery cost calculators.
Freight Calculator
Calculate freight cost based on weight, dimensions, distance, and shipping mode.
Shipping Volume Calculator
Calculate the volume and volumetric weight of shipments for air and sea freight.
Container Loading Calculator
Calculate how many boxes or pallets fit in a 20ft or 40ft shipping container.
Pallet Calculator
Calculate how many boxes fit on a pallet and total pallet count for a shipment.
Dimensional Weight Calculator
Calculate dimensional (volumetric) weight for FedEx, UPS, DHL, and USPS shipments.
Delivery Cost Calculator
Calculate the total cost of last-mile delivery per package and per route.
Logistics Cost Calculator
Calculate total logistics cost as percentage of revenue including warehousing, transport, and inventory.
Solar & Energy Calculators
Solar savings, EV charging, electricity bill & carbon footprint calculators.
Solar Battery Calculator
Calculate the battery storage size needed to power your home from solar energy.
Solar Savings Calculator
Calculate how much you can save on electricity bills by installing solar panels.
EV Charging Cost Calculator
Calculate the cost to charge an electric vehicle at home or at public charging stations.
Electricity Bill Calculator
Calculate your electricity bill from appliance usage, kWh consumption, and utility rates.
Carbon Footprint Calculator
Calculate your personal or household carbon footprint from energy, transport, food, and lifestyle.
Generator Size Calculator
Calculate the generator size (kW/kVA) needed to power your home or business.
Automotive Calculators
Car depreciation, fuel economy, tire size & lease vs buy calculators.
Car Depreciation Calculator
Calculate how much your car depreciates each year and its future resale value.
Vehicle Loan Affordability Calculator
Calculate the maximum car price you can afford based on income, down payment, and loan terms.
Tire Size Calculator
Compare tire sizes, calculate speedometer error, and find equivalent tire options.
EV Range Calculator
Calculate electric vehicle range based on battery capacity, efficiency, and driving conditions.
Fuel Economy Calculator
Calculate fuel economy (MPG/L per 100km), fuel cost per mile, and annual fuel spend.
Road Trip Fuel Calculator
Calculate fuel cost for any road trip based on distance, MPG, and fuel price.
Lease vs Buy Car Calculator
Compare total cost of leasing vs buying a car over any ownership period.
Pet Calculators
Dog age, cat age, pet calorie & pet weight calculators.
Dog Age Calculator
Convert your dog's age to human years using breed-size adjusted formulas.
Cat Age Calculator
Convert your cat's age to human years using the official AAFP age chart.
Dog Pregnancy Calculator
Calculate a dog's due date and pregnancy stages from the mating date.
Pet Calorie Calculator
Calculate daily calorie needs for dogs and cats based on weight, age, and activity level.
Pet Weight Calculator
Check if your dog or cat is at a healthy weight and calculate ideal weight range.
Wedding & Event Calculators
Wedding guest, catering cost, event budget & party food calculators.
Wedding Guest Calculator
Calculate venue size, catering quantities, and per-head cost for any guest count.
Catering Cost Calculator
Estimate catering cost per person for weddings, corporate events, and parties.
Event Budget Calculator
Plan and track the total budget for any event across all expense categories.
Drink Calculator
Calculate how many drinks, bottles of wine, beer, and spirits you need for any event.
Party Food Calculator
Calculate how much food you need for any party based on guests, time, and meal type.
Frequently Asked Questions
Yes β every calculator on this site is completely free to use. There are no paid tiers, no premium features, and no hidden charges. We are funded by non-intrusive advertising, which keeps all tools free for everyone, forever.
No account or registration is required for any calculator on BrainyCalculators. Open any tool, enter your values, and get your results instantly. We do not ask for your name, email address, or any personal information.
All calculators use industry-standard formulas sourced from authoritative bodies such as the WHO, NIST, IEC, and financial regulatory agencies. Each tool is cross-validated before publication and reviewed regularly. For financial and health tools, results are estimates based on the inputs you provide β individual outcomes depend on real-world factors the formula cannot capture. See our Calculator Methodology page for full details.
Yes. Every calculator is fully responsive and tested on smartphones and tablets. Results update instantly as you type, with no page reload needed. The site also works well in low-bandwidth conditions because all calculations run in your browser rather than on a server.
We review and update calculators on a weekly basis. Tax calculators are updated at the start of each new tax year. Health calculators are updated whenever the underlying clinical guideline changes. If you spot an error, use the contact page to report it and we aim to investigate within five working days.
Our calculators are designed as informational and educational tools. They are suitable for getting quick estimates and checking your own workings. For decisions with significant financial, legal, health, or engineering consequences, we recommend verifying results with a qualified professional. See our Disclaimer for the specific limitations that apply to each category.