The SI base unit is the kilogram (kg). Enter a value to convert across all units.
Common units used in the US and UK. Enter a value to convert.
Specialized units used for jewelry, pharmacy, and other areas.
Mass & Weight Conversion Guide
Metric System
The metric system is a decimal system of measurement based on the kilogram. Conversions are straightforward multiples or fractions of 10, such as grams (1/1000 kg), milligrams (1/1,000,000 kg), and metric tons (1000 kg).
Imperial & US Customary
Based on the avoirdupois pound (exactly 0.45359237 kg). An ounce is 1/16 of a pound, a stone is 14 pounds, a short ton (US) is 2,000 pounds, and a long ton (UK) is 2,240 pounds.
Specialized Units
Carat is the standard unit for gemstones and pearls (1 ct = 200 mg). Grain is a historical unit based on the weight of a single cereal seed, still used in pharmacy, archery, and firearms (1 gr ≈ 64.7989 mg).
Key Conversion Factors
| Basic Conversions | Tonnage Conversions |
|---|---|
| 1 kg = 1000 g = 35.27 oz ≈ 2.205 lb | 1 tonne = 0.98 UK ton = 1.10 US ton |
| 1 lb = 16 oz ≈ 0.454 kg = 453.59 g | 1 US ton = 2000 lb ≈ 0.893 UK ton ≈ 0.907 tonne |
| 1 catty (台斤) = 16 taels (台兩) = 600 g = 0.6 kg | - |
Frequently Asked Questions
How many pounds are in a kilogram?
One kilogram is approximately 2.20462 pounds. Conversely, one pound is exactly 0.45359237 kilograms.
What is the difference between a long ton, short ton, and metric ton?
A metric ton (tonne) is exactly 1,000 kg. A short ton (used in the US) is 2,000 lb (≈ 907.18 kg). A long ton (used in the UK) is 2,240 lb (≈ 1,016.05 kg).
How many ounces are in a pound?
There are exactly 16 ounces (oz) in a standard avoirdupois pound (lb).