About this tool
Type a weight in pounds and get kilograms straight away. The converter multiplies by the exact international factor, 1 lb = 0.45359237 kg, so the only rounding is in the digits shown. You can also type in the kilogram box to go the other way. Everything runs in your browser and nothing is uploaded.
How to use it
Enter the number of pounds in the left box. The kilogram figure appears on the right as you type. Decimals work, so 154.3 lb is fine. If you already know the kilograms and want pounds, use the right-hand box instead, or open the kg to lbs converter, which is written from the metric side.
How to convert lbs to kg by hand
Multiply the pounds by 0.45359237. For quick mental math, halve the number and then take off about a tenth of that half: 200 lb halved is 100, minus 10 is 90, and the exact answer is 90.72 kg. The shortcut lands within about 1% for most everyday weights, which is fine for luggage but not for anything regulated.
Pounds to kilograms reference table
| Pounds | Kilograms |
|---|---|
| 1 lb | 0.45 kg |
| 5 lb | 2.27 kg |
| 10 lb | 4.54 kg |
| 25 lb | 11.34 kg |
| 35 lb | 15.88 kg |
| 45 lb | 20.41 kg |
| 50 lb | 22.68 kg |
| 70 lb | 31.75 kg |
| 100 lb | 45.36 kg |
| 150 lb | 68.04 kg |
| 200 lb | 90.72 kg |
| 250 lb | 113.40 kg |
Where people need lbs to kg
- Airline baggage: a 50 lb checked bag is 22.68 kg, and a 70 lb bag is 31.75 kg. Many non-US airlines state limits in kilograms only, so a bag packed to the pound limit can be a little over or under.
- Gym weights: a 45 lb plate is 20.41 kg, a 35 lb plate is 15.88 kg and a 10 lb plate is 4.54 kg. A 45 lb bar loaded with two 45 lb plates a side is 225 lb, which is 102.06 kg. Metric gyms use 20 kg bars and 20 kg plates, so the numbers are close but not identical.
- Body weight: 150 lb is 68.04 kg and 200 lb is 90.72 kg. Doctors, fitness apps and charts outside the US usually work in kilograms.
- Shipping and imports: parcel services and customs forms often want kilograms, even when the seller lists pounds.
Why the pound has an exact metric value
Before 1959 the US and UK pounds differed very slightly. An international agreement that year set the avoirdupois pound at exactly 0.45359237 kg, and that is the value every modern converter should use. So you do not need to ask which pound is meant when you convert for everyday purposes. Troy pounds, used for precious metals, are a separate unit and are not covered here.
Things to watch out for
Do not confuse "lb" with "lbs": both mean pounds, and lbs is just the plural. Be careful with stones too. In the UK, body weight is often given in stone and pounds, such as 11 st 4 lb, and that has to be turned into pounds first (one stone is 14 lb) before converting. Finally, round at the end, not in the middle of a calculation, so errors do not build up.
Frequently asked questions
1 pound is exactly 0.45359237 kilograms, which rounds to about 0.454 kg. That means 1 lb is roughly 454 grams.
Multiply 150 by 0.45359237. The result is 68.04 kg when rounded to two decimals.
Yes. They use the same factor. Going from pounds to kilograms you multiply by 0.45359237, and going from kilograms to pounds you divide by it (or multiply by about 2.20462).