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Mass Calculator
Convert a mass between kilograms, grams, milligrams, metric tonnes, pounds, ounces, stones and US short tons.
Mass Calculator
Convert mass between units — kg, g, lb, oz, ton and more
m = ρ × V | 1 kg = 2.20462 lbs = 1000 g
Mass in All Units
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Grams (g)
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Milligrams (mg)
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Pounds (lb)
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Ounces (oz)
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Stone
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Metric Ton
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Mass hides behind other measurements more often than it is weighed directly: sometimes you know the volume and the material, sometimes the weight on some world. This calculator finds mass from density and volume, or from weight and local gravity.
How to use this calculator
- Choose the method: density and volume, or weight (with gravity).
- Enter the values you have.
- Press calculate to see the mass in kilograms (and other units).
Mass stays, weight travels
Your mass is the same on Earth, the Moon and in deep space; your weight is gravity's local opinion of it. Engineers exploit the density route used here whenever a thing is too large, too hot or too distant to put on scales, from tank contents to asteroid estimates.
Frequently asked questions
How do I calculate mass from density?
Mass = density × volume. A litre (0.001 m³) of a material with density 800 kg/m³ has a mass of 0.8 kg.
How do I get mass from weight?
Mass = weight divided by gravitational acceleration (about 9.81 m/s² on Earth). A weight of 981 N means a mass of 100 kg.
What is the SI unit of mass?
The kilogram. Grams, tonnes and pounds convert through it, and this calculator handles the conversions with the calculation.