Mass Calculator

Calculate mass from density & volume, convert weight to mass using gravity, or convert between all mass units. Results shown in every unit simultaneously.

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m=pV
Mass from Density & Volume

Enter density and volume to calculate mass. Supports all major density and volume units. Select a material preset to auto-fill density.

m = ρ × V — mass = density × volume
Result shown in your chosen unit — change dropdown to convert
Significant Figures:
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W/g
Weight to Mass Calculator

Convert weight (force) to mass using Newton's second law: m = F/g. Select a planet or body to use its gravitational acceleration, or enter a custom value.

m = W ÷ g — mass = weight ÷ gravity
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mg
Mass to Weight Calculator

Calculate the weight (gravitational force) of a mass on any planet or body. W = m × g

W = m × g — weight = mass × gravity
conv
Mass Unit Converter

Enter any mass value and convert it to all common units simultaneously.

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Mass vs Weight Guide
Key Formulas
m = ρ × V  —  mass = density × volume
m = W ÷ g  —  mass = weight ÷ gravitational acceleration
W = m × g  —  weight = mass × gravitational acceleration

SI unit of mass: kilogram (kg)
SI unit of weight: Newton (N)
Standard gravity on Earth: g = 9.80665 m/s²
Mass vs Weight — What's the Difference?
Mass is the amount of matter in an object. It is constant regardless of location — your mass is the same on Earth, Moon, or in space.

Weight is the gravitational force acting on a mass. It changes depending on where you are — you weigh 6x less on the Moon than on Earth, but your mass is unchanged.

Example: A 70 kg person has a weight of 686 N on Earth (70 × 9.807), but only 113 N on the Moon (70 × 1.62).
Gravity on Different Planets (m/s²)
Sun: 274.0  |  Jupiter: 24.79  |  Neptune: 11.15
Earth: 9.807  |  Venus: 8.870  |  Saturn: 10.44
Mars: 3.720  |  Mercury: 3.700  |  Moon: 1.620
Pluto: 0.620  |  Space (free fall): 0

Note: Gravity on Earth varies slightly by latitude and altitude. Standard gravity = 9.80665 m/s².
Common Mass Unit Conversions
1 kg = 1,000 g = 1,000,000 mg
1 kg = 2.20462 lb = 35.27396 oz
1 kg = 0.157473 stone
1 metric ton = 1,000 kg = 1.10231 US short tons
1 US short ton = 2,000 lb = 907.185 kg
1 UK long ton = 2,240 lb = 1,016.05 kg
1 oz = 28.3495 g  |  1 lb = 453.592 g
1 carat = 0.2 g (used for gemstones)
1 grain = 0.0648 g (used for gunpowder, medicine)