Pounds to kilograms in one step
Going the other way from the usual American measurement? Plenty of forms, gyms, and clinics outside the US want your weight in kilograms, and a US scale only gives you pounds. This converts the two cleanly.
One factor does all the work. 1 pound = 0.453592 kilograms. Enter pounds, read kilograms. The dropdown lets you reverse it or bring in ounces and stones when a value mixes units.
The exact relationship
kilograms = pounds x 0.453592
Here’s the clean part: a pound is defined as exactly 0.45359237 kg by international agreement. So this isn’t an approximation that drifts. We carry enough decimals that even a 250 lb figure lands within a gram of the true value. Round to one decimal place for everyday use and nobody will ever notice.
Common pound values
| Pounds | Kilograms |
|---|---|
| 1 lb | 0.45 kg |
| 10 lb | 4.54 kg |
| 25 lb | 11.34 kg |
| 50 lb | 22.68 kg |
| 100 lb | 45.36 kg |
| 150 lb | 68.04 kg |
| 180 lb | 81.65 kg |
| 200 lb | 90.72 kg |
That 50 lb line shows up everywhere in shipping. It’s the breakpoint where many carriers stop charging standard rates and tack on a heavy-package surcharge, and it equals just under 22.7 kg.
Real reasons people convert this direction
Moving US body weight to metric is the classic case. A doctor’s office abroad, a dive certification card, a pilot’s medical, a martial arts weight class, all of them usually log kilograms. Someone who weighs 175 lb is right around 79.4 kg.
Shipping and logistics lean on it hard. International couriers bill by kilogram and apply dimensional-weight rules in kg, so a warehouse pulling US pound figures off a scale has to convert before generating a label. Get it wrong and the quoted price won’t match what the carrier charges.
It also smooths out recipes and nutrition. A US recipe calling for 2 lb of potatoes becomes 0.91 kg, which matters if your kitchen scale is metric. Bulk grocery pricing flips the same way when you’re comparing a per-pound US price to a per-kilo one abroad.
Watch out for these
A pound (lb) is not a stone. UK weight charts often use stones, where 1 stone = 14 lb, so “13 stone 4” is 186 lb, about 84.4 kg. If you only convert the pounds portion and forget the stones, you’ll be way off.
Also keep ounces separate. There are 16 ounces in a pound, so 6 lb 8 oz is 6.5 lb, which is 2.95 kg. Convert the whole figure, not just the round pounds.
The tool does every calculation in your browser. Nothing you type is uploaded or stored on a server, and once the page is open it keeps working without a connection.
FAQ
How many kg is 1 pound?
About 0.453592 kg, a little under half a kilogram. So 2 lb is roughly 0.91 kg.
What’s the quick mental version?
Halve the pounds, then trim off around 10 percent. 100 lb halves to 50, minus 5, gives about 45 kg. The exact figure is 45.36.
Is this accurate enough for medical or legal use?
Yes. The factor is an exact international definition and we show several decimals, so the result is precise to within a gram for normal ranges.
How do I convert pounds and ounces together?
Turn the ounces into a decimal first (divide by 16), add it to the pounds, then convert. 8 lb 4 oz is 8.25 lb, which is 3.74 kg.
Is anything sent to a server?
No. It’s all client-side math, so your weight values never leave the device.