Convert Pounds to Kilograms (lbs to kg)
1 pound is defined as exactly 0.45359237 kilograms — an internationally agreed exact value fixed in 1959, not a rounded approximation.
Quick converter
Common conversions
Common body-weight values in pounds and their exact kilogram equivalents.
| Pounds (lb) | Kilograms (kg) |
|---|---|
| 100 lb | 45.36 kg |
| 120 lb | 54.43 kg |
| 140 lb | 63.50 kg |
| 150 lb | 68.04 kg |
| 160 lb | 72.57 kg |
| 180 lb | 81.65 kg |
| 200 lb | 90.72 kg |
| 220 lb | 99.79 kg |
Rounded for readability. Use the converter above for exact decimals.
How it works
This direction is for when you already have a weight in pounds — a US body weight, a package weight on a US shipping label, a gym plate, a medication dose — and need the kilogram figure for a metric context: a non-US form, a scale calibrated in kilograms, or comparing it to a product spec listed in kilograms.
Body weight is the most common trigger: someone who tracks their weight in pounds — say, 150 lb — needs the kilogram figure for a non-US medical form, a fitness app built for a metric audience, or a conversation with someone who thinks in kilograms. 150 lb converts to about 68.04 kg.
Medication and supplement dosing sometimes lists a "per kilogram of body weight" figure, which only works if you know your weight in kilograms. Someone whose weight is recorded in pounds on their chart needs to convert before applying a dosage formula written in mg/kg — getting this wrong by using the pound number directly can mean a dose that's off by more than double.
US shipping and product weights are the other common case: a package listed at 20 lb on a US carrier's label needs converting to kilograms (about 9.07 kg) to compare against a courier's metric weight limit, or to check against a product spec sheet from a non-US manufacturer that only lists kilograms.
US grocery prices are quoted per pound, which makes them look cheaper than a per-kilogram price until the units are lined up. Meat advertised at $4.99 a pound is $11.00 a kilogram, because the price scales the opposite way to the weight: divide by 0.45359237, or multiply by about 2.2, to move a per-pound price to a per-kilogram one. Deli counters add another step by selling in fractions, so a quarter pound is 113.4 g and a half pound is 226.8 g.
Frequently asked questions
- How many kilograms is 150 lbs?
- 150 lb equals about 68.04 kg (150 × 0.45359237). That is a common adult body weight reference point in pound-based countries, roughly in the middle of many BMI charts for average height.
- How do I convert lbs to kg without a calculator?
- Divide the pound value by 2.2 for a close estimate, or multiply by 0.4536 for a more precise one. For example, 150 lb ÷ 2.2 ≈ 68.2, close to the exact 68.04 kg.
- My weight is recorded in pounds, but a medication dose is given in mg per kilogram — how do I convert safely?
- Convert your pound weight to kilograms first (multiply by 0.45359237), then multiply that kilogram figure by the mg/kg dose. Using the pound number directly in a mg/kg formula overstates the dose by more than double, since a pound is less than half a kilogram — always convert the weight, never the dose.
- A US shipping label says 20 lb — how many kilograms is that for a courier with a metric weight limit?
- 20 lb converts to about 9.07 kg. Couriers and postal services outside the US almost always publish weight limits in kilograms, so converting a US-labeled package weight before shipping avoids a surprise at drop-off if the parcel is close to the limit.
Related calculators
Share
Embed this calculator
Paste this code into your site to embed a live, working version of this calculator.
Last updated: 2026-08-22