Weight Converter
Enter a value, choose your source and target units, and instantly convert between milligrams, grams, kilograms, tonnes, ounces, pounds, and stone.
How the Weight Converter formula works
As with length, every unit routes through a common base (grams):
value_in_grams = value × factor_of_source_unit result = value_in_grams / factor_of_target_unit
For example, 1 pound = 453.592 grams and 1 stone = 6,350.29 grams.
Step-by-step calculation
- Multiply the entered value by its unit's conversion factor to get grams.
- Divide that gram value by the target unit's conversion factor.
- Round to a sensible number of decimal places for the target unit.
Worked example
Converting 154 lb to kilograms: 154 × 453.592 g = 69,853 g = 69.85 kg. Converting 10 stone to pounds: 10 × 6,350.29 g ÷ 453.592 g/lb = 140 lb.
Frequently asked questions
Is a metric tonne the same as a US ton?
No — a metric tonne is 1,000 kg (about 2,204.6 lb), while a US short ton is 2,000 lb (about 907.2 kg). This calculator uses the metric tonne; check the unit carefully if precision matters.
Why is weight sometimes called mass?
In everyday and commercial use, 'weight' and 'mass' are used interchangeably and this calculator treats them the same way. In physics, mass is unit-independent while weight technically depends on gravity, but that distinction doesn't affect unit conversion.