The international avoirdupois pound has been defined as exactly 0.45359237 kg since 1959. So, like inches, the factor is definitional rather than measured.
Working the other way, 1 kg = 2.20462262 lb. Doubling and adding 10% is a good mental shortcut — 70 kg → 140 + 14 = 154 lb, and the true answer is 154.3.
| Kilograms | Pounds | Stones and pounds |
|---|---|---|
| 1 kg | 2.20 lb | 0 st 2.2 lb |
| 2 kg | 4.41 lb | 0 st 4.4 lb |
| 5 kg | 11.02 lb | 0 st 11.0 lb |
| 10 kg | 22.05 lb | 1 st 8.0 lb |
| 20 kg | 44.09 lb | 3 st 2.1 lb |
| 30 kg | 66.14 lb | 4 st 10.1 lb |
| 40 kg | 88.18 lb | 6 st 4.2 lb |
| 50 kg | 110.23 lb | 7 st 12.2 lb |
| 60 kg | 132.28 lb | 9 st 6.3 lb |
| 70 kg | 154.32 lb | 11 st 0.3 lb |
| 80 kg | 176.37 lb | 12 st 8.4 lb |
| 90 kg | 198.42 lb | 14 st 2.4 lb |
| 100 kg | 220.46 lb | 15 st 10.5 lb |
| 120 kg | 264.55 lb | 18 st 12.6 lb |
| 150 kg | 330.69 lb | 23 st 8.7 lb |
Stones, if you are reading from the UK or Ireland
Body weight in Britain and Ireland is usually given in stones and pounds. 1 stone = 14 pounds = 6.35029 kg. Note that the stone is essentially unused in the US, so "eleven stone" will not be understood by an American audience — and Australia and New Zealand went metric decades ago, so kilograms are correct there.
Mass and weight are not the same thing
This is the distinction that matters and that almost every converter glosses over.
Mass is how much matter something contains. It does not change with location. Kilograms, grams and pounds-mass measure this.
Weight is the force gravity exerts on that mass. It changes with location. The correct SI unit is the newton.
In everyday use, "weight" means mass, and every conversion on this site treats it that way — which is right for cooking, luggage, body weight and shipping. It becomes wrong in physics and engineering, where a 70 kg mass weighs about 686 N on Earth and about 113 N on the Moon while its mass never changes.
A metric ton (tonne) is 1,000 kg = 2,204.6 lb. A US short ton is 2,000 lb = 907.2 kg. A UK long ton is 2,240 lb = 1,016 kg. Three different "tons" within about 12% of each other, which has caused real freight and construction errors.
Ounces
1 oz = 28.3495 g, and there are 16 ounces to a pound. Do not confuse this with the fluid ounce, which measures volume, not weight — and which differs between the US and the UK. Recipes that say "8 oz flour" mean weight; "8 fl oz milk" means volume. See our cooking conversions guide.
Weight conversion, any units Kilograms, pounds, grams, ounces, stones, metric tons and milligrams.
Open the converter