Weight conversion
Convert Pounds to Kilograms
1 pound equals 0.4536 kilograms. To convert pounds to kilograms, multiply the number of pounds by 0.4536 (or divide by 2.2046).
Pounds to kilograms is what you need for metric medical charts, international forms, scientific work, and gym or shipping figures quoted in kg. Enter any pound value and the kilograms appear instantly, with the exact factor shown so the result is easy to verify.
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Computed at full precision in your browser; the result is rounded for display.
How to convert pounds to kilograms
Formula
kilograms = pounds × 0.45359237 pounds = kilograms × 2.2046One pound is defined as exactly 0.45359237 kilograms, so this conversion is exact by definition.
| Pounds | Kilograms |
|---|---|
| 1 lb | 0.4536 kg |
| 5 lb | 2.268 kg |
| 10 lb | 4.536 kg |
| 20 lb | 9.072 kg |
| 50 lb | 22.68 kg common bag limit |
| 100 lb | 45.36 kg |
| 150 lb | 68.04 kg adult body weight |
| 160 lb | 72.57 kg |
| 180 lb | 81.65 kg |
| 200 lb | 90.72 kg |
Worked example
A medication is dosed per kilogram but the patient's weight is on the chart as 160 pounds. Multiply 160 × 0.4536 to get 72.6 kg, the figure the dose calculation needs. The same single step converts any pound weight — a 45-lb gym plate is 20.4 kg, a 50-lb bag limit is 22.7 kg.
Shortcut. Quick estimate: halve the pounds and subtract about 10%. 160 lb → 80 − 8 = 72 kg, very close to the exact 72.6 kg.
Good to know
This is a straight multiply-by-0.4536 conversion. In healthcare especially, doing it accurately matters: a 10% error from a sloppy factor can change a weight-based drug dose, so use the full 0.45359237 or at least 0.4536. To go back to pounds, multiply kilograms by 2.2046.
Frequently asked questions
How many kg is 1 pound?
One pound is 0.4536 kilograms. Multiply any pound figure by 0.4536, or divide by 2.2046, to get kilograms.
What is 150 lbs in kg?
150 pounds equals about 68 kg. 100 lb is 45.4 kg, 180 lb is 81.6 kg and 200 lb is 90.7 kg.
How do I convert pounds to kg quickly?
Halve the pounds and take off about 10%. 200 lb → 100 − 10 = 90 kg, close to the exact 90.7 kg.
Is the pound-to-kilogram conversion exact?
Yes. A pound is defined as exactly 0.45359237 kilograms, so only the displayed decimals are rounded.
Why does medical dosing use kg?
Most drug doses are calculated per kilogram of body weight, so a weight given in pounds must be converted to kg first — multiply by 0.4536.