Convert Pounds to Kilograms
Pounds to kilograms is the everyday conversion for turning an imperial weight into metric — body weight, luggage, a bag of something at the store. One pound is exactly 0.45359237 kilograms, so the number always gets smaller, roughly cut to a bit under half.
Pounds to Kilograms conversion table
| Pounds (lb) | Kilograms (kg) |
|---|---|
| 1 | 0.453592 |
| 2 | 0.907185 |
| 3 | 1.360777 |
| 5 | 2.267962 |
| 10 | 4.535924 |
| 20 | 9.071847 |
| 50 | 22.679619 |
| 100 | 45.359237 |
| 500 | 226.796185 |
| 1,000 | 453.59237 |
The formula
To convert pounds to kilograms, multiply the weight in pounds by 0.45359237:
kilograms = pounds × 0.45359237
A worked example
A standard gym plate is labelled 45 lb, and you want it in kilograms:
45 × 0.45359237 = 20.4 kg
So a 45-pound plate is about 20.4 kg — which is why metric gyms use 20 kg plates as the near-equivalent.
Why it's exact
Since 1959 the international avoirdupois pound has been defined as exactly 0.45359237 kilograms. That single agreed value is what makes every pounds-to-kilograms conversion precise — useful when the weight feeds into something official, like a medical record or a freight document, where an estimate wouldn't do.
When you'll use it
Converting your weight for a metric health form, working out luggage against a kilogram allowance, matching imperial gym weights to metric plates, or turning a pounds-labelled product into kilograms to compare prices per kilo.
Frequently asked questions
How many kilograms are in a pound?
Exactly 0.45359237 kilograms. The international pound is defined by that value, so the conversion is exact rather than approximate.
What's a quick mental estimate for pounds to kilograms?
Halve it, then shave a little off. So 150 lb is a touch under 75 kg (about 68), and 100 lb is roughly 45 kg. Use the exact factor when it counts.
Is this the right conversion for body weight?
Yes. Body weight uses avoirdupois pounds, which is exactly what this factor is for. Troy units are only for precious metals and don't come into it.