About this calculator
Type a number, choose the unit you have and the unit you want, and this converter gives you the answer at once, along with the same weight and mass in every other unit it knows.
Every conversion factor is exact by definition wherever one exists, and each result shows the working so you can check it.
Worked examples
Real numbers, worked out by the same calculator. Press “Use these numbers” to try one above.
10 lb to kg
- kilograms (kg)
- 4.5359237 kg
- grams (g)
- 4,535.9237 g
- milligrams (mg)
- 4,535,923.7 mg
- tonnes (t)
- 0.0045359237 t
- ounces (oz)
- 160 oz
- stone (st)
- 0.714285714286 st
- US short tons
- 0.005 US short tons
- UK long tons
- 0.00446428571429 UK long tons
10 lb is 4.5359237 kg.
Show the working
- Change to the base unit (kg): 10 lb × 0.45359237 = 4.5359237 kg.
- Change to kg: 4.5359237 ÷ 1 = 4.5359237 kg.
12 st to kg
- kilograms (kg)
- 76.20351816 kg
- grams (g)
- 76,203.51816 g
- milligrams (mg)
- 76,203,518.16 mg
- tonnes (t)
- 0.07620351816 t
- pounds (lb)
- 168 lb
- ounces (oz)
- 2,688 oz
- US short tons
- 0.084 US short tons
- UK long tons
- 0.075 UK long tons
12 st is 76.20351816 kg.
Show the working
- Change to the base unit (kg): 12 st × 6.35029318 = 76.20351816 kg.
- Change to kg: 76.20351816 ÷ 1 = 76.20351816 kg.
500 g to oz
- ounces (oz)
- 17.6369809748 oz
- kilograms (kg)
- 0.5 kg
- milligrams (mg)
- 500,000 mg
- tonnes (t)
- 0.0005 t
- pounds (lb)
- 1.10231131092 lb
- stone (st)
- 0.0787365222089 st
- US short tons
- 0.00055115565546 US short tons
- UK long tons
- 0.00049210326381 UK long tons
500 g is 17.6369809748 oz.
Show the working
- Change to the base unit (kg): 500 g × 0.001 = 0.5 kg.
- Change to oz: 0.5 ÷ 0.028349523125 = 17.6369809748 oz.
How to convert by hand
Every mass unit is a fixed multiple of the kilogram. Multiply by the size of the unit you have (in kilograms), then divide by the size of the unit you want. For example, 10 lb × 0.45359237 = 4.5359237 kg.
The pound has been defined as exactly 0.45359237 kg since 1959. An ounce is one sixteenth of a pound, and a stone is 14 pounds.
Conversion factors used
Each unit is stored as its size in kg. The sizes below are the ones this converter uses.
| Unit | Size |
|---|---|
| kilograms (kg) | 1 kg |
| grams (g) | 0.001 kg |
| milligrams (mg) | 0.000001 kg |
| tonnes (t) | 1,000 kg |
| pounds (lb) | 0.45359237 kg |
| ounces (oz) | 0.028349523125 kg |
| stone (st) | 6.35029318 kg |
| US short tons | 907.18474 kg |
| UK long tons | 1,016.0469088 kg |
Common conversions
| From | To |
|---|---|
| 1 kg | 2.20462262185 lb |
| 1 lb | 0.45359237 kg |
| 1 oz | 28.349523125 g |
| 1 st | 14 lb |
| 1 t | 1,000 kg |
| 100 g | 3.52739619496 oz |
| 70 kg | 11.0231131092 st |
| 1 US short tons | 907.18474 kg |
Stone, tonnes and tons
In the UK, body weight is often given in stone (14 lb, about 6.35 kg). A metric tonne is 1,000 kg. The US short ton is 2,000 lb (907.18 kg) and the UK long ton is 2,240 lb (1,016.05 kg), so “ton” can mean three slightly different things.
Frequently asked questions
How many pounds are in a kilogram?
One kilogram is about 2.2046 pounds.
How many pounds are in a stone?
A stone is 14 pounds.
Is a ton the same as a tonne?
No. A tonne is 1,000 kg. A US ton is 907.18 kg and a UK ton is 1,016.05 kg.
How accurate is this converter?
It uses the exact defined factors wherever they exist and shows up to 12 significant digits, so the results are accurate to far more digits than you will normally need.
Formulas tested against hand-worked answers. Last reviewed 29 September 2026. These calculators do arithmetic only; they are not financial, tax or legal advice.