Weight Converter
Convert between 14 weight and mass units, from milligrams and carats to tonnes and troy ounces, with live results and the exact formula shown.
How weight conversion works
All units convert through kilograms, the SI base unit of mass. Each unit has one fixed factor (1 lb = 0.45359237 kg exactly), so any pair converts in a single multiplication step with no chained rounding error.
Avoirdupois, troy and metric
Everyday weights use avoirdupois ounces and pounds. Precious metals use troy ounces (heavier: 31.1 g vs 28.35 g), and gemstones use carats (0.2 g). Stones are still common for body weight in the UK, equal to 14 pounds.