⚖️ Weight & Mass Converter

Convert between metric and imperial weight units — milligrams, grams, kilograms, tonnes, ounces, pounds, stone, and US/UK tons. Type in any field, every other one updates instantly.

Try:
70 kg 150 lb 12 stone 16 oz 1 tonne
Metric
Imperial & US
Other
Copied

About the Weight & Mass Converter

The Weight Converter turns any mass or weight into every other common unit at once. Type in kilograms and see pounds, ounces, stone, grams, and tonnes update at the same time. Every field is both an input and an output — change one and the rest follow instantly. Nothing you type is sent anywhere; conversion runs in your browser and works offline once the page has loaded.

Common uses

  • Body weight — 70 kg = 154.32 lb = 11 stone 0.3 lb.
  • Cooking & baking — a stick of butter is 4 oz / 113.4 g; a pound of flour is 453.6 g.
  • Shipping & freight — parcels priced by kg abroad, by lb in the US.
  • Gym & fitness — 100 kg on the bar is 220.46 lb; 45 lb plates are 20.41 kg each.
  • Precious metals & medication — grams and milligrams for accurate dosing.

Supported units

Metric: milligram (mg), gram (g), kilogram (kg), metric tonne (t = 1000 kg).

Imperial & US: ounce (oz), pound (lb), stone (st = 14 lb), US short ton (2000 lb), UK long ton (2240 lb).

Combined: stone + pounds (as spoken in the UK — "twelve stone six").

Exact conversion ratios

All conversion uses the internationally agreed-upon avoirdupois system, which is legally exact:

  • 1 pound = 0.45359237 kilograms exactly (the base definition)
  • 1 kilogram = 2.20462262185... pounds
  • 1 ounce = 1/16 pound = 28.349523125 grams
  • 1 stone = 14 pounds = 6.35029318 kilograms
  • 1 US short ton = 2000 pounds = 907.18474 kg
  • 1 UK long ton = 2240 pounds = 1016.0469088 kg
  • 1 metric tonne = 1000 kg = 2204.62262... lb

Mass vs weight — a note

Strictly speaking, mass is a measure of matter (kilogram is the SI unit) while weight is a force (newton is the SI unit). In everyday use — and on this page — "weight" means mass, which is how bathroom scales, kitchen scales, and shipping labels use the word too. If you need force in newtons, multiply mass in kg by 9.80665 m/s² (Earth's standard gravity).

Privacy

All conversion runs client-side in JavaScript. Your inputs never leave the browser.

Frequently asked questions

One kilogram is exactly 2.20462262… pounds. The definition works the other way: 1 pound = 0.45359237 kg exactly, and everything else follows from that.
A stone is a British imperial weight unit equal to 14 pounds, or about 6.35 kilograms. It's still the standard way to talk about body weight in the UK and Ireland ("twelve stone six").
A US short ton is 2000 pounds (~907 kg). A UK long ton is 2240 pounds (~1016 kg). Both differ from the metric tonne, which is exactly 1000 kg (~2204.62 lb). This page shows all three.
The Stone + pounds row has two separate boxes — type whole stone in the first, remaining pounds in the second. Either box on its own is fine (leave pounds empty for whole stone, or stone empty for pounds only).
No. Weight conversion is arithmetic — no server round-trip is needed and none is made.