Weight Converter
Convert between weight and mass units instantly: milligrams, grams, kilograms, tonnes, ounces, pounds, and stones. Free, 100% in your browser.
Reference
How does weight conversion work?
Weight conversion uses fixed ratios between units. This tool converts through kilograms as the base unit — your input is first converted to kilograms, then from kilograms to every other unit. The international avoirdupois pound is defined as exactly 0.45359237 kg (since 1959), and 1 ounce = 1/16 of a pound. The metric tonne equals exactly 1,000 kg.
Unit reference
Metric system: milligram (mg), gram (g), kilogram (kg), tonne (t) — based on powers of 10, used worldwide. Imperial/US: ounce (oz) = 28.35 g, pound (lb) = 16 ounces = 453.59 g, stone (st) = 14 pounds = 6.35 kg — used primarily in the US and UK. The metric tonne (1,000 kg) is distinct from the US short ton (2,000 lb ≈ 907 kg) and the imperial long ton (2,240 lb ≈ 1,016 kg).
Common use cases
Cooking — convert between grams and ounces for recipes from different countries. Fitness — convert body weight between kg and lbs, or track weights in the gym. Shipping — convert package weights between metric and imperial for international shipping. Science — convert lab measurements between milligrams and grams. Travel — understand luggage weight limits in different unit systems.
Privacy
All calculations run 100% in your browser. No data is sent to any server.