Pounds to kilograms
Last updated
One pound is exactly 0.45359237 kilograms. Not approximately. The 1959 international yard and pound agreement fixed it, so this is a definition rather than a measurement. Going the other way, one kilogram is 2.20462 pounds.
This number is why the rest of this site exists, which the next section explains.
There are two pounds, and the trap is worse than the two ounces
Most people know the troy ounce is heavier than a standard ounce. Almost nobody expects the troy pound to be lighter. It is, and by a wide margin.
The everyday pound
0.45359237 kg
Exact — 1959 agreement
Holds 16 standard ounces. Body weight, parcels, groceries, gym plates. If something says "lb" without qualification, this is it.
The precious-metals pound
0.3732417216 kg
Exact — 12 troy ounces
Holds 12 troy ounces. Twelve of the heavier unit still comes to less than sixteen of the lighter one, so this pound is 17.71% lighter.
| Unit | Standard | Troy | Troy differs by |
|---|---|---|---|
| One ounce | 28.349523125 g | 31.1034768 g | +9.71% heavier |
| Ounces in its pound | 16 | 12 | 4 fewer |
| One pound | 453.59237 g | 373.2417216 g | −17.71% lighter |
| One pound in kg | 0.45359237 kg | 0.3732417216 kg | −0.0804 kg |
In practice the troy pound is a museum piece: bullion is priced per troy ounce, never per troy pound. But if you meet "pound" in a metals listing, check which one is meant before converting. The full troy comparison →
Where the ounce comes from
The ounce is not defined on its own. It is one sixteenth of a pound. Divide 453.59237 g by sixteen and you get 28.349523125 g, which is the standard ounce. Every ounce figure this site publishes descends from the pound, and the pound descends from the kilogram, by the 1959 agreement.
That is the whole chain: the kilogram is the standard, the pound is defined against it exactly, and the ounce is a sixteenth of the pound. Nothing in it is measured or approximated. It is why we can publish 28.349523125 g rather than "about 28.35", and why the methodology page can name an authority for every figure instead of citing an average.
Pounds to kilograms
Every value from the exact definition. Ounces are shown too, because a pound is sixteen of them and a lot of scales read that way.
| Pounds | Kilograms | Grams | Standard oz |
|---|---|---|---|
| 1 lb | 0.454 kg | 453.6 g | 16 oz |
| 2 lb | 0.907 kg | 907.2 g | 32 oz |
| 3 lb | 1.361 kg | 1,360.8 g | 48 oz |
| 5 lb | 2.268 kg | 2,268 g | 80 oz |
| 7 lb | 3.175 kg | 3,175.1 g | 112 oz |
| 10 lb | 4.536 kg | 4,535.9 g | 160 oz |
| 12 lb | 5.443 kg | 5,443.1 g | 192 oz |
| 14 lb | 6.35 kg | 6,350.3 g | 224 oz |
| 15 lb | 6.804 kg | 6,803.9 g | 240 oz |
| 20 lb | 9.072 kg | 9,071.8 g | 320 oz |
| 25 lb | 11.34 kg | 11,339.8 g | 400 oz |
| 30 lb | 13.608 kg | 13,607.8 g | 480 oz |
| 40 lb | 18.144 kg | 18,143.7 g | 640 oz |
| 50 lb | 22.68 kg | 22,679.6 g | 800 oz |
| 60 lb | 27.216 kg | 27,215.5 g | 960 oz |
| 70 lb | 31.751 kg | 31,751.5 g | 1,120 oz |
| 80 lb | 36.287 kg | 36,287.4 g | 1,280 oz |
| 90 lb | 40.823 kg | 40,823.3 g | 1,440 oz |
| 100 lb | 45.359 kg | 45,359.2 g | 1,600 oz |
| 120 lb | 54.431 kg | 54,431.1 g | 1,920 oz |
| 150 lb | 68.039 kg | 68,038.9 g | 2,400 oz |
| 200 lb | 90.718 kg | 90,718.5 g | 3,200 oz |
| 250 lb | 113.398 kg | 113,398.1 g | 4,000 oz |
Kilograms to pounds
The same conversion reversed, with the pounds-and-ounces reading beside it, since that is how body weight and parcels are usually quoted.
| Kilograms | Pounds | Pounds and ounces | Standard oz |
|---|---|---|---|
| 1 kg | 2.2046 lb | 2 lb 3.3 oz | 35.3 oz |
| 2 kg | 4.4092 lb | 4 lb 6.5 oz | 70.5 oz |
| 3 kg | 6.6139 lb | 6 lb 9.8 oz | 105.8 oz |
| 5 kg | 11.0231 lb | 11 lb 0.4 oz | 176.4 oz |
| 10 kg | 22.0462 lb | 22 lb 0.7 oz | 352.7 oz |
| 15 kg | 33.0693 lb | 33 lb 1.1 oz | 529.1 oz |
| 20 kg | 44.0925 lb | 44 lb 1.5 oz | 705.5 oz |
| 25 kg | 55.1156 lb | 55 lb 1.8 oz | 881.8 oz |
| 30 kg | 66.1387 lb | 66 lb 2.2 oz | 1,058.2 oz |
| 40 kg | 88.1849 lb | 88 lb 3 oz | 1,411 oz |
| 50 kg | 110.2311 lb | 110 lb 3.7 oz | 1,763.7 oz |
| 60 kg | 132.2774 lb | 132 lb 4.4 oz | 2,116.4 oz |
| 70 kg | 154.3236 lb | 154 lb 5.2 oz | 2,469.2 oz |
| 75 kg | 165.3467 lb | 165 lb 5.5 oz | 2,645.5 oz |
| 80 kg | 176.3698 lb | 176 lb 5.9 oz | 2,821.9 oz |
| 90 kg | 198.416 lb | 198 lb 6.7 oz | 3,174.7 oz |
| 100 kg | 220.4623 lb | 220 lb 7.4 oz | 3,527.4 oz |
| 120 kg | 264.5547 lb | 264 lb 8.9 oz | 4,232.9 oz |
Doing it in your head
Pounds to kilograms: halve it, then take off a tenth. 100 lb halves to 50, minus 5 gives 45 kg. The true answer is 45.36 kg, so you are within a percent.
Kilograms to pounds: double it, then add a tenth. 45 kg doubles to 90, plus 9 gives 99 lb. The true answer is 99.2 lb.
Both shortcuts work because 0.45359237 is close to 0.45, and 2.2046 is close to 2.2. Use the full figure when the number matters, which the tables above already do.
Where the pound still gets used
- Body weight in the US. Straight pounds. In the UK and Ireland it is stone and pounds instead, at 14 lb to the stone.
- Newborns. Quoted as pounds and ounces in the US and UK, which is a format rather than a unit. That conversion →
- Recipes and packaging. Always the avoirdupois pound, and its ounce is always the standard one. Never troy.
- Precious metals. Priced per troy ounce, not per pound of either kind. If you are weighing metal, work in grams or troy ounces and skip pounds entirely.
Frequently asked
How many kilograms is one pound?
One pound is exactly 0.45359237 kilograms, or 453.59237 grams. That figure is a definition rather than a measurement: the 1959 international yard and pound agreement fixed it, and every ounce value follows from it, since an ounce is one sixteenth of a pound.
How many pounds is one kilogram?
One kilogram is 2.2046 pounds, or 2 lb 3.3 oz. The exact figure is 2.20462262185 pounds, which is 1 divided by 0.45359237.
Is a pound 500 grams?
No. A pound is 453.59237 grams, so treating it as 500 g overstates it by 46.41 grams, about 10.2%. The confusion is real though: in many Latin American markets a "libra" means a metric half kilo of exactly 500 g, which is a trade convention rather than the international pound. If a figure came from a market stall it may well mean 500 g; if it came from a label, a scale, or a recipe, it means 453.59237 g.
Is a troy pound the same weight in kilograms?
No, and it is lighter. A troy pound is 0.3732417216 kilograms against the ordinary pound at 0.45359237, making it 17.71% lighter. This catches people out because the troy ounce is 9.71% heavier than a standard ounce. The pound flips the direction because it holds only 12 troy ounces where an ordinary pound holds 16.
How do you convert pounds to kilograms in your head?
Halve the pounds, then take off a tenth of that. So 100 lb halves to 50, minus 5 gives 45 kg, against a true 45.36 kg. Going the other way, double the kilograms and add a tenth: 45 kg doubles to 90, plus 9 gives 99 lb, against a true 99.2 lb.