Weight Converter
Convert between US, imperial, and metric weight units.
Type a weight, pick your units, get the conversion. Supports milligrams through tons in one tool.
Examples: 150 lb to kg = 68.04 kg. 1 stone to lb = 14 lb. 500 g to oz = 17.64 oz.
How weight conversion works
All weights convert through grams as the base unit. Your input is converted to grams, then from grams to your target unit. This handles US customary (ounces, pounds), imperial (stones, long tons), and metric (mg, g, kg, tonnes) in one consistent system.
Common conversions
- 1 ounce = 28.35 grams
- 1 pound = 16 ounces = 453.59 grams
- 1 kilogram = 2.205 pounds = 35.27 ounces
- 1 stone = 14 pounds = 6.35 kg (used in UK for body weight)
- 1 US ton = 2,000 pounds (short ton)
- 1 metric ton = 1,000 kilograms = 2,204.62 pounds
Weight vs mass (technical note)
Scientifically, "weight" measures gravitational force (newtons) while "mass" measures matter (kilograms). In everyday usage, "weight" almost always means mass. This calculator treats them interchangeably the way ordinary use does. If you need scientific weight in newtons, multiply mass in kg by 9.80665 (Earth gravity) or whatever local gravity applies.