Weight Converter
Convert kilograms, grams and tonnes to pounds, ounces, stone and tons — with the exact international pound (0.45359237 kg) behind every result. Results update as you type; exact factors shown.
One pound is 0.4536 kilograms — see the exact factor, not a rounded rule of thumb.
How the weight converter works
Mass converts through the kilogram. The avoirdupois pound has been exactly 0.45359237 kg since 1959, so an ounce is 28.349523125 g and a stone (14 lb) is 6.35029318 kg. A US short ton is 2,000 lb; an imperial long ton is 2,240 lb; a metric tonne is 1,000 kg.
The US uses customary units (US gallon, short ton, °F) in daily life; NIST SP 811 gives the exact SI factors.
Common mass conversions
| From | To | Units |
|---|---|---|
| 1 kg | 2.2046 lb | kilogram to pounds |
| 1 lb | 0.4536 kg | pound to kilograms |
| 1 st | 6.3503 kg | stone to kilograms |
| 1 oz | 28.3495 g | ounce to grams |
| 100 g | 3.5274 oz | grams to ounces |
| 1 t | 2,204.6226 lb | tonne (metric ton) to pounds |
| 1 US ton | 907.1847 kg | US ton (short) to kilograms |
| 1 long ton | 1,016.0469 kg | imperial ton (long) to kilograms |
| 10 st | 140 lb | stones to pounds |
| 70 kg | 11.0231 st | kilograms to stones |
Units in this converter and their exact factors
| Unit | Symbol | One unit in kilograms |
|---|---|---|
| milligram | mg | 0.000001 kilogram |
| gram | g | 0.001 kilogram |
| kilogram | kg | 1 kilogram |
| tonne (metric ton) | t | 1,000 kilogram |
| ounce | oz | 0.0283495231 kilogram |
| pound | lb | 0.45359237 kilogram |
| stone | st | 6.35029318 kilogram |
| US ton (short) | US ton | 907.18474 kilogram |
| imperial ton (long) | long ton | 1,016.0469088 kilogram |
FAQFrequently asked questions about mass conversion
How many pounds are in a kilogram?
About 2.2046 pounds. Exactly, 1 kg = 1 / 0.45359237 lb.
How many pounds are in a stone?
Exactly 14 pounds, or 6.35 kg. Stone is still used for body weight in the UK and Ireland.
What is the difference between a ton and a tonne?
A metric tonne is 1,000 kg. A US (short) ton is 2,000 lb = 907.2 kg; an imperial (long) ton is 2,240 lb = 1,016 kg.
How many grams are in an ounce?
28.35 g. Note that a troy ounce, used for precious metals, is 31.1035 g and is not included here.
Is weight the same as mass?
In everyday use yes; strictly, these units measure mass and weight is the force gravity exerts on it. The conversions are the same either way.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Institute of Standards and Technology (NIST) — United States's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.