Weight Conversion Guide: kg, lbs, Ounces and Stone
November 9, 2026
Kilograms, pounds, ounces and stone all measure the same thing, so converting between them is a single multiplication. The factors are exact by definition, which makes them easy to trust once you know them.
The short answer
- Kilograms to pounds: multiply by 2.20462. 70 kg is 154.32 lb.
- Pounds to kilograms: multiply by 0.45359237. 150 lb is 68.04 kg.
- Ounces to grams: multiply by 28.3495. 8 oz is 226.8 g.
- Stone to kilograms: multiply by 6.35029. One stone is 14 lb.
The kg to lb converter and the lb to kg converter handle any value.
Where the factors come from
Since 1959 the pound has been defined as exactly 0.45359237 kilograms, agreed between the United States, the United Kingdom and other Commonwealth countries. Every other factor follows from it:
- An ounce is 1/16 of a pound, so it's exactly 28.349523125 grams.
- A stone is 14 pounds, so it's exactly 6.35029318 kilograms.
- A US ton is 2,000 pounds, so it's exactly 907.18474 kilograms.
The kilogram itself has been defined through a fixed value of the Planck constant since 2019, rather than by a metal cylinder kept near Paris. For everyday conversions nothing changed.
Kilograms to pounds table
| Kilograms | Pounds |
|---|---|
| 1 kg | 2.20 |
| 5 kg | 11.02 |
| 10 kg | 22.05 |
| 20 kg | 44.09 |
| 50 kg | 110.23 |
| 60 kg | 132.28 |
| 70 kg | 154.32 |
| 80 kg | 176.37 |
| 90 kg | 198.42 |
| 100 kg | 220.46 |
Pounds to kilograms table
| Pounds | Kilograms |
|---|---|
| 100 lb | 45.36 |
| 120 lb | 54.43 |
| 150 lb | 68.04 |
| 180 lb | 81.65 |
| 200 lb | 90.72 |
| 250 lb | 113.40 |
Stone, for body weight in the UK and Ireland
Body weight in the UK and Ireland is often given in stone and pounds, such as 11 st 4 lb. To convert, turn it all into pounds first: 11 × 14 + 4 = 158 lb, which is 71.67 kg.
| Stone | Kilograms |
|---|---|
| 8 st | 50.8 |
| 9 st | 57.2 |
| 10 st | 63.5 |
| 11 st | 69.9 |
| 12 st | 76.2 |
| 13 st | 82.6 |
| 14 st | 88.9 |
| 15 st | 95.3 |
| 16 st | 101.6 |
The stone to kg converter and the kg to stone converter work in either direction.
Grams and ounces in the kitchen
US recipes often give ounces, and most of the rest of the world uses grams.
- 4 oz is 113.4 g, and 8 oz (half a pound) is 226.8 g.
- 250 g is 8.82 oz, and 500 g is 17.64 oz, a little over a pound.
- One gram is about 0.035 oz, so small amounts of spices or yeast are much easier to weigh in grams.
Use the grams to ounces converter or the ounces to grams converter for exact amounts.
Shortcuts you can do in your head
- kg to lb: double it, then add 10%. 70 kg doubles to 140, plus 14 is 154; the exact answer is 154.32 lb.
- lb to kg: halve it, then take off 10%. 150 lb halves to 75, less 7.5 is 67.5; the exact answer is 68.04 kg. That's within about 1%.
- oz to g: multiply by 30, then take off a little. 8 oz × 30 is 240; the exact figure is 226.8 g. Multiplying by 28 gets closer.
Weight and mass
In everyday speech, weight and mass mean the same thing, and that's what this guide converts. In physics they're different. Mass, measured in kilograms or pounds, is how much matter something contains. Weight is the force gravity puts on that mass, measured in newtons. A scale measures force and shows it as mass, assuming standard Earth gravity. If you need to turn a force in newtons into kilograms, see newtons to kilograms.
Common mistakes
- Confusing tons. A US ton is 2,000 lb, or 907.18 kg. A metric tonne is 1,000 kg, or 1.1023 US tons. The UK long ton is different again. If a figure matters, check which ton is meant, or use the metric tonne to US ton converter.
- Mixing fluid ounces and ounces. A fluid ounce measures volume, an ounce measures weight. They only line up for water and liquids of similar density.
- Using ordinary ounces for gold and silver. Precious metals are priced in troy ounces, which are heavier than the ounces in this guide.
- Treating 11 st 4 lb as 11.4 stone. The 4 is pounds, not tenths of a stone. 11 st 4 lb is about 11.29 stone.
Related conversions
- Every weight unit at once. The weight and mass converter covers milligrams through US tons.
- Body measurements. For heights in feet, inches and centimeters, see the length conversion chart.