Weight Converter

Convert mass units: mg, g, kg, metric tons, lb, oz, stone, US tons, and imperial tons. Live cross-conversion grid with kitchen, shipping, and bullion reference notes.

Recipe Scaling and Kitchen Weight Conversions

BrainyCalculators editorial insight — unique to this tool

Professional bakers in the US work in ounces and pounds while European recipes list grams — a 250 g bag of flour is roughly 8.8 oz, but butter sticks (113 g each) do not convert cleanly to metric blocks. Jewelers and pharmacists still use troy ounces (31.1 g) versus avoirdupois ounces (28.35 g), a distinction that trips up precious-metal pricing. Indian grocery labels often show kg while street vendors quote per 100 g, making quick mental conversion essential at the counter.

When to use this calculator

Use this tool when you need mass/weight units for cooking, shipping labels, gym plates, or nutrition labels — not force (newtons) or pressure. Enter the value you have and pick the unit your source document uses.

Reference	Value	Context
1 US cup all-purpose flour	~120 g	Baking — volume ≠ weight
1 lb ground beef	453.6 g	USDA retail packaging
1 troy oz gold	31.103 g	Bullion vs kitchen oz
1 quintal (India)	100 kg	Agricultural commodity quotes

Not what you need? For structural steel or pipe mass by dimensions, use the Steel Weight or Pipe Weight calculators. For force in newtons, use the Force calculator.

Converting length, temperature, or multiple types?

This page converts mass/weight only. For length, temperature, and more in one tool, use the Unit Converter →

Value

From Unit

Enter a value above to see all unit conversions.

Common Weight Conversions

1 kilogram (kg) = 2.205 pounds (lbs)

1 pound (lb) = 453.6 grams

1 stone = 14 pounds / 6.35 kg

1 ounce (oz) = 28.35 grams

1 metric ton = 1,000 kg / 2,205 lbs

1 US ton = 907.2 kg / 2,000 lbs

1 imperial ton = 1,016 kg / 2,240 lbs

100 grams = 3.527 ounces

What is a Weight (Mass) Converter?

A weight converter translates mass between metric and imperial units — grams to pounds, kilograms to stone, ounces to milligrams. Kitchen ounces (avoirdupois, 28.35 g) differ from troy ounces for precious metals (31.103 g); this page handles mass, not force (newtons) or pressure (psi).

Use this page for recipe scaling, parcel weight, gym progress, and bullion quotes when the label is already in mass units. Carriers also use dimensional weight, but that is a length-volume rule — start here only for actual mass conversion.

For one-dimensional distance (mm, feet, miles), use the Length Converter. For temperature scales, the Temperature Converter. For multiple unit categories in one place, the Unit Converter.

Worked Examples: Dosing, Baggage, and Bullion

1

Pediatric dose at 15 mg/kg

A child weighs 44 lb. Convert to kg first: 44 × 0.453592 = 19.96 kg. Dose = 15 × 19.96 ≈ 299 mg. Skipping the lb→kg step is the most common clinical conversion error.
2

23 kg checked-bag allowance

Airline limit 23 kg → 23 × 2.20462 = 50.7 lb. Repack on a bathroom scale reading pounds before heading to a metric-ticket counter.
3

Gold bar quoted in troy ounces

A 10 ozt bar × 31.1035 g/ozt = 311.0 g. Using everyday ounces (28.35 g) would understate bullion mass by about 9.7%.
4

Freight invoice in metric tonnes

Shipment billed at 2.4 t → 2,400 kg → 5,291 lb. Confirm whether the contract tonne is metric (1,000 kg) or a US short ton (907 kg).

How the Weight Converter Works

Formula, assumptions, and calculation steps for this conversion tool.

Methodology

Conversion calculators multiply by fixed conversion factors after identifying the source and destination units.

Calculation Steps

Choose the input unit and output unit.
Enter the amount to convert.
Apply the standard conversion factor.
Return the converted value with unit labels.

Assumptions and Limits

Conversions use standard factors unless a regional variant is selected.
Rounding is applied for readability.
Temperature and pressure conversions may require formulas rather than simple multiplication.

Frequently Asked Questions

Why do pharmacy labels use milligrams but US bathroom scales use pounds?

Clinical dosing and body-weight tracking evolved on different unit traditions. A 10 mg tablet dose is independent of whether the patient weighs 70 kg or 154 lb, but converting the patient weight correctly is still required for mg/kg prescriptions.

How do I convert kg to lb for airline baggage?

Multiply kilograms by 2.20462. A 23 kg allowance equals about 50.7 lb. Airlines enforce the limit in whichever unit their ticket states, so convert before repacking at the airport.

What is the difference between avoirdupois and troy ounces?

Everyday goods use avoirdupois ounces (28.35 g). Precious metals use troy ounces (31.10 g). Jewellery priced per ounce without naming the type can be wrong by nearly 10%.

Are US tons and metric tonnes interchangeable?

No. A US short ton is 2,000 lb (907 kg), a UK long ton is 2,240 lb (1,016 kg), and a metric tonne is exactly 1,000 kg. Bulk commodity contracts must name the ton type explicitly.

How do I convert stone to kilograms directly?

Multiply stone by 6.35029. Eleven stone is about 70.0 kg. Converting stone to pounds first and then to kilograms adds avoidable rounding error.

Real-World Applications

💊

Medication Doses by Body Mass

Clinical dosing often starts in mg per kg, while older records or US intake forms may list patient weight in pounds. Converting 176 lb to 79.8 kg changes every weight-based dose calculation downstream.

🧳

Airline Baggage Thresholds

A 23 kg checked-bag limit is about 50.7 lb; a 70 lb heavy-bag threshold is about 31.8 kg. Travelers comparing airline rules need the exact mass boundary before repacking.

🍞

Baking by Weight

Professional recipes specify flour, sugar, and butter in grams because cups vary by packing density. Converting ounces to grams keeps hydration ratios and dough formulas stable.

🚛

Freight and Pallet Labels

Export documents may require kg while domestic warehouse systems show lb. Accurate conversion avoids customs mismatches and keeps pallet loads within lift-truck ratings.

🥇

Bullion and Precious Metals

Gold and silver are traded in troy ounces, not everyday ounces. One troy ounce is 31.103 g, so jewellery and bullion conversions need the correct ounce family.

🏋️

Gym Plate Loading

Powerlifting meets and gym equipment mix kg plates with lb bars. Converting total loaded weight keeps training percentages consistent across facilities.

Weight Conversion Mistakes to Avoid

Using cooking ounces for bullion

Gold listings in troy ounces converted with the everyday ounce factor understate mass by about 9.7%. Always confirm whether the ounce is avoirdupois or troy before pricing jewellery or bars.

Treating lb and kg as a 2:1 shortcut

Dividing pounds by 2 instead of 2.20462 is fine for luggage estimates but unsafe for medication dosing, freight billing, or scientific work where small errors compound.

Confusing mass with force

Kilograms measure mass; newtons measure weight as force. Everyday kitchen and shipping conversions assume Earth gravity, but engineering load calculations need the correct physics units.

Mixing short ton and metric tonne on invoices

A contract priced per tonne but fulfilled per short ton creates a 10% quantity mismatch. Verify the unit on both the purchase order and the weighbridge ticket.

Ignoring decimal places on clinical conversions

Rounding a pediatric weight from 33.1 lb to 33 lb before converting to kg can change a weight-based drug dose. Keep one extra decimal through the conversion step.

Weight Conversion Quick Reference (Trade & Shipping)

Unit	= Kilograms	= Pounds	= Grams
1 Kilogram	1 kg	2.20462 lb	1,000 g
1 Pound (avoirdupois)	0.453592 kg	1 lb	453.592 g
1 Troy Ounce	0.031103 kg	0.06857 lb	31.103 g
1 Stone	6.35029 kg	14 lb	6,350.29 g
1 Metric Ton	1,000 kg	2,204.62 lb	1,000,000 g
1 US Short Ton	907.185 kg	2,000 lb	907,185 g

References

BIPM. The International System of Units (SI), 9th Edition. Bureau International des Poids et Mesures, 2019.
NIST. Weights and Measures in the United States (SP 811). National Institute of Standards and Technology, 2008.
Weights and Measures Act 1985. Schedule 1 — Definitions of Units of Measurement. UK Parliament.
ISO 80000-4:2019. Quantities and Units — Mechanics. International Organization for Standardization.
USMA. Metric System of Measurement. United States Metric Association, 2023.