Weight Converter
Convert between any weight and mass units - from atomic masses to cosmic scales with comprehensive precision
Popular Weight Conversions
⚛️ Atomic
Electron mass
9.109 × 10⁻³¹ kg
👤 Human
Average adult
70 kg (154 lbs)
🚗 Vehicle
Average car
1.5 tonnes
🌍 Planetary
Earth mass
5.97 × 10²⁴ kg
The kilogram is the only SI base unit defined by a physical object - the International Prototype Kilogram in Paris.
A pound was historically defined as the weight of 7,000 grains of barley.
The stone (14 pounds) is still commonly used in the UK and Ireland for measuring body weight.
One troy ounce (used for precious metals) weighs about 10% more than a regular ounce.
The metric ton is exactly 1,000 kilograms, while the US ton is 2,000 pounds (907.2 kg).
At the quantum level, mass and energy are interchangeable according to Einstein's E=mc².