Mass & Weight Converter
Convert between mass and weight units: kilograms, grams, metric tons, pounds, ounces, stones, US/UK tons, newtons, kilogram-force, and more with consistent rounding.
Mass conversion
Reference: 1 kg = 2.20462262 lb = 35.27396195 oz = 0.1574730444 st; 1 metric tonne (t) = 1000 kg.
Mass equivalents
Weight equivalents
How to Use This Converter
Pick the Mass or Weight tab, type in your value, choose the units you have and the units you want, then click Calculate or wait for the inputs to refresh. The grid on the right instantly mirrors the chosen value across the most common units for quick lookups.
Methodology
The converter uses precise SI-based factors and standard gravity (g = 9.80665 m/s²) so physics-minded readers can trace every step. Mass conversions normalize to kilograms before branching into grams, pounds, stones, ounces, and tonnes. Weight conversions normalize to newtons, which makes it easy to compare kgf, lbf, dyn, and kilonewtons with consistent rounding.
Displayed figures round at the final stage to 6 decimal places (2 decimals for dynes) while retaining the base value for higher accuracy when you change units again.
Mass vs Weight
Mass is intrinsic and doesn’t change with location. It’s measured in kilograms, grams, pounds, ounces, stones, and tons. Weight is a force: the pull of gravity on that mass. On Earth, weight is mass × 9.80665 m/s², and this calculator automatically handles that relationship when you switch tabs.
FAQ
Can I enter a very small mass like micrograms?
Yes. µg is supported because the converter normalizes every value to kilograms first, preserving precision even for tiny quantities.
Why do you show both US short ton and UK long ton?
1 US short ton = 2000 lb (≈ 907.18474 kg) while 1 UK long ton = 2240 lb (≈ 1016.0469 kg). Mixing them leads to invoice errors, so both are listed separately for clarity.
How do I get weight on the Moon?
Weight = mass × lunar gravity (1.62 m/s²). The main weight tab assumes Earth gravity; for other planets, multiply the result manually by the local gravitational acceleration.