Instant answers for finance, health, math & everyday life — plus logic games and puzzles to sharpen your mind. All free, forever.
BrainyCalculators is a free collection of over 350 online calculators covering every area of modern life — from personal finance and health metrics to engineering, statistics, and everyday maths. Every tool on this site is completely free to use, requires no sign-up or account, and works instantly in your browser without sending any data to external servers.
Managing money effectively starts with accurate numbers. Our finance section includes tools for mortgage and EMI planning, compound interest and investment growth, loan affordability, credit card payoff timelines, retirement savings, GST and tax estimation, and much more. Whether you are comparing loan offers, working out how long it will take to clear a credit card balance, or projecting what a monthly investment will grow to over 20 years, our tools give you the precise figures you need to make informed decisions. All financial calculators use standard industry formulas — the same equations used by financial advisors, banks, and actuaries in professional practice.
Our health section covers Body Mass Index (BMI), Basal Metabolic Rate (BMR), Total Daily Energy Expenditure (TDEE), body fat percentage, ideal weight ranges, calorie needs, heart rate zones, blood alcohol content, pregnancy due dates, and more. These calculators follow guidelines from the World Health Organization, the National Institutes of Health, and other recognised health authorities. They are designed as screening tools to help you understand your own numbers — they do not replace professional medical advice, but they give you an informed starting point for conversations with your doctor.
From basic arithmetic to calculus, statistics, geometry, and physics, our maths and engineering sections handle the full range of quantitative problems. Students working through homework problems, engineers checking structural calculations, data scientists computing confidence intervals, or teachers preparing lesson materials will all find tools suited to their needs. Our scientific calculator, z-score tool, standard deviation calculator, quadratic solver, and matrix calculators are among the most-visited tools on the site.
Some of the most popular tools on BrainyCalculators solve the straightforward questions that come up in everyday life — unit converters, age calculators, tip and bill splitters, date and time calculators, percentage finders, and fuel cost estimators. These tools are designed to be fast and intuitive, giving you an answer in seconds without needing to remember a formula or reach for a textbook. No account, no subscription, no hidden fees — just the answer you need, immediately.
Beyond calculators, BrainyCalculators is also home to a growing collection of free brain puzzles and logic games — including Direction Lock, Number Link Escape, Weight Balance, Laser Mirror, Pipe Builder Logic, Color Merge Maze, Arrow Escape, Gravity Shift, Sokoban Warehouse, Shape Fit, and Brain Grid Escape. Each puzzle offers multiple difficulty levels, daily challenges with streak tracking, and instant in-browser play with no downloads or sign-up. Whether you want to sharpen your spatial reasoning, practise logical deduction, or just take a quick mental break between calculations, our daily puzzles are completely free and built for every skill level.
Track Escape Puzzle
Most used calculators by our visitors
Calculate return on investment and measure the profitability of any investment.
Calculate your monthly EMI for home, car, or personal loans instantly.
Estimate monthly mortgage payments including principal, interest, taxes, and insurance.
Calculate returns on your Systematic Investment Plan (SIP) investments.
Calculate percentages, percentage change, and percentage of a number easily.
Add, subtract, multiply, and divide fractions. Simplify fractions and convert to decimals.
Full-featured scientific calculator with trigonometry, logarithms, and advanced math functions.
Solve linear and quadratic equations for x step by step.
Solve quadratic equations ax² + bx + c = 0 using the quadratic formula.
Calculate sin, cos, tan, and their inverses in degrees or radians.
Calculate the area of any shape — circle, triangle, rectangle, trapezoid, and more.
Calculate the area, circumference, diameter, and radius of any circle.
Challenge your mind with our collection of brain puzzles, logic games, math puzzles, IQ challenges, and problem-solving riddles. Whether you're looking to improve critical thinking, sharpen reasoning skills, or simply have fun, our free online puzzles are designed for students, professionals, and puzzle enthusiasts of all ages.
Brain puzzles help improve memory, concentration, logical reasoning, and problem-solving abilities. Regular puzzle solving can enhance cognitive skills and mental agility while providing an enjoyable learning experience. Explore our collection of free online puzzles, brain teasers, and logic challenges to keep your mind sharp.
Find the right calculator for every need
New tools added regularly
Calculate return on investment and measure the profitability of any investment.
Calculate your monthly EMI for home, car, or personal loans instantly.
Estimate monthly mortgage payments including principal, interest, taxes, and insurance.
See how your investments grow over time with the power of compounding.
Calculate returns on your Systematic Investment Plan (SIP) investments.
Calculate percentages, percentage change, and percentage of a number easily.
Add, subtract, multiply, and divide fractions. Simplify fractions and convert to decimals.
Full-featured scientific calculator with trigonometry, logarithms, and advanced math functions.
Tips, guides and financial advice
Learn everything about logic puzzle games, their benefits, popular types, solving strategies, and tips to improve your critical thinking skills.
Read more →
Learn the key differences between fixed and variable interest rates, including formulas, examples, benefits, risks, and real-world applications. Discover which option may be better for loans, mortgages, and savings accounts.
Read more →
Learn how inflation reduces the purchasing power of your savings over time. Discover simple formulas, real-world examples, common mistakes, and smart strategies to protect your money from rising prices.
Read more →Built for accuracy, speed, and simplicity
All calculations run in your browser — zero server round-trips, zero waiting.
Optimised for phones, tablets, and desktops equally. No app needed.
We never store or share your inputs. All calculations are private by design.
Every calculator shows the formula it uses so you can verify results independently.
Every calculator on BrainyCalculators is built on well-established mathematical and financial formulas drawn from authoritative sources — including the Consumer Financial Protection Bureau, the World Health Organization, the National Institutes of Health, actuarial standards, and peer-reviewed academic literature. We don't invent proprietary formulas. We implement the same equations used by financial advisors, doctors, engineers, and scientists in professional practice.
For example, our EMI calculator uses the standard amortisation formula — the same calculation your bank uses. Our BMI calculator follows WHO classification guidelines. Our compound interest calculator applies the mathematically exact formula, not an approximation. Where a field has multiple accepted standards (such as BMR, which has several validated formulas), we implement all variants and clearly explain when to use each.
Each calculator goes through a structured development and review process before it is published:
We review our calculators on an ongoing basis. Tax calculators are updated annually to reflect current tax brackets, thresholds, and allowances. Health calculators are updated whenever clinical guidelines change. Financial calculators are reviewed against current regulatory standards. Where a calculator relies on current rates — such as standard inflation assumptions or reference interest rates — we note this clearly and direct users to authoritative sources for the most current figures.
New calculators are added regularly across all categories. Our goal is to be the single destination you need for any quantitative question, from the simple (what percentage is X of Y?) to the complex (what is the net present value of this investment?)
Our tools serve a wide range of users across every background:
All calculators and supporting content on BrainyCalculators are produced and reviewed by our in-house editorial team. Finance and tax calculators are cross-referenced against official government publications and regulatory guidance. Health calculators follow published clinical guidelines. Mathematical calculators are validated against textbook standards and authoritative reference tables.
Yes. Every calculator on BrainyCalculators is 100% free with no registration required. There are no premium tiers or paywalled features.
Our calculators use standard financial and mathematical formulas sourced from authoritative bodies including the WHO, CFPB, and academic literature. Results are accurate for everyday use but should not replace professional financial, medical, or legal advice.
No. All calculations happen directly in your browser. We do not send, store, or share your input data with any third party.
Absolutely. Every calculator is designed mobile-first and works seamlessly on phones, tablets, and desktops without needing an app.
Tax and finance calculators are reviewed at least annually. Health calculators are updated when clinical guidelines change. We add new tools regularly — subscribe to our newsletter to stay updated.
If you spot an error in any calculator or content, please use our Contact page. We take accuracy seriously and review all reports promptly.
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