Conversions
Weight Converter
Enter a weight in any unit to see it in all the others at once.
Worked example
A body weight of 165 lb in kilograms
- 1 lb = 0.45359237 kg exactly
- 165 × 0.45359237 = 74.84 kg
Where this goes wrong
Assuming a ton is a ton
Three different tons are in daily use and they differ by more than 10%. A US short ton is 2,000 lb (907.18 kg), a tonne is 1,000 kg (2,204.6 lb), and a UK long ton is 2,240 lb (1,016 kg). On a 20-ton aggregate delivery the choice moves nearly two tonnes. This page uses the US short ton, and says so in the row label.
Questions
- How many pounds are in a kilogram?
- About 2.20462. The exact relationship runs the other way: a pound is *defined* as 0.45359237 kilograms, agreed internationally in 1959. Every pound-to-kilogram figure you see is that definition, and every kilogram-to-pound figure is its reciprocal, which does not terminate.
- Is weight the same as mass?
- Not in physics — mass is how much matter there is, weight is the force gravity exerts on it. In everyday use, and on this page, the two are treated as the same because scales on Earth report mass in weight units. It matters if you are calculating a force; it does not if you are buying potatoes.
- What is an ounce, exactly?
- One sixteenth of a pound, so 28.349523125 g exactly. Do not confuse it with a fluid ounce, which measures volume and has no fixed relationship to weight — a fluid ounce of honey and a fluid ounce of oil weigh different amounts.