Mass
Calculator
Calculate mass from density and volume, find weight on any planet, solve net/gross/tare mass, and convert between all mass units instantly.
Your Weight on Different Planets
Based on a 70 kg person (Earth weight ≈ 686 N / 154 lbs). Use Panel 2 for your exact mass.
| Location | Gravity (m/s²) | Weight (N) | Weight (lbf) | vs Earth |
|---|---|---|---|---|
| ☀️ Sun | 274.0 | 19,180 N | 4,311 lbf | ×28.0 |
| 🌍 Earth | 9.807 | 686.5 N | 154.3 lbf | ×1.00 (reference) |
| 🟡 Jupiter | 24.79 | 1,735 N | 390 lbf | ×2.53 |
| 🔵 Neptune | 11.15 | 780.5 N | 175.5 lbf | ×1.14 |
| 🪐 Saturn | 10.44 | 730.8 N | 164.3 lbf | ×1.06 |
| ♀ Venus | 8.870 | 620.9 N | 139.6 lbf | ×0.905 |
| ⬛ Uranus | 8.690 | 608.3 N | 136.8 lbf | ×0.886 |
| 🔴 Mars | 3.720 | 260.4 N | 58.6 lbf | ×0.379 |
| ☿ Mercury | 3.700 | 259.0 N | 58.2 lbf | ×0.377 |
| 🌕 Moon | 1.620 | 113.4 N | 25.5 lbf | ×0.165 |
| ⬜ Pluto | 0.620 | 43.4 N | 9.8 lbf | ×0.063 |
Mass Never Changes — Weight Does
An astronaut with a mass of 80 kg has exactly 80 kg of mass on Earth, the Moon, Mars, and in deep space. But their weight changes dramatically — 784 N on Earth, 130 N on the Moon, 298 N on Mars. Bathroom scales measure weight (force) but display mass assuming Earth's gravity of 9.807 m/s².
Gross mass: Total mass of product + all packaging. What the shipping label shows.
Tare mass: Mass of the empty container, packaging, pallet, or vehicle alone.
Net mass: Mass of the product itself. Net = Gross − Tare. Food packaging always shows net weight — the amount of food, not including the box or bottle. In shipping, tare weight of the truck is subtracted from the gross weight to get the payload net mass.
Atomic mass unit (u or Da): 1 u = 1.66054 × 10⁻²⁷ kg. Carbon-12 atom = exactly 12 u by definition.
Molar mass: Mass of 1 mole (6.022 × 10²³ particles) in g/mol. Numerically equals atomic/molecular mass. Water (H₂O) = 18.015 g/mol. To find mass: m = n × M, where n = moles and M = molar mass.
Example: 2 mol of NaCl (M = 58.44 g/mol) → mass = 2 × 58.44 = 116.88 g
Mass Formulas — Calculate Mass, Weight & More
Mass is the fundamental measure of how much matter an object contains. Unlike weight, mass does not depend on gravity and remains constant everywhere in the universe. The four most common mass calculations are covered by our calculator.
Mass from Density and Volume
Weight from Mass
Net Mass (Gross − Tare)
Mass Unit Conversion Factors
Mass vs Weight — Understanding the Difference
One of the most common confusions in physics — and everyday life — is treating mass and weight as the same thing. They are related but fundamentally different quantities.
Mass: The Intrinsic Property
Mass is a scalar quantity that measures the amount of matter in an object. It is measured in kilograms (SI) or pounds-mass (lb) in the US system. Mass is the same everywhere — a 70 kg astronaut has exactly 70 kg of mass on Earth, the Moon, Mars, or in deep space. Mass is what determines an object's inertia: how hard it is to accelerate.
Weight: The Gravitational Force
Weight is the gravitational force acting on a mass: W = mg. It is measured in Newtons (SI) or pound-force (lbf). Weight changes with location — the same 70 kg person weighs 686 N on Earth, 113 N on the Moon (g = 1.62 m/s²), and 1,735 N on Jupiter (g = 24.79 m/s²). When we say someone "weighs 70 kg," we're technically stating their mass, not their weight in proper physics terms.
Why Bathroom Scales Show Mass, Not Weight
A bathroom scale measures weight (gravitational force) using a spring or load cell, then divides by Earth's standard gravity (9.80665 m/s²) to display mass in kg or lb. This works perfectly on Earth's surface but would give the wrong reading on the Moon or Mars — a 70 kg person would appear to "weigh" only 11.6 kg on a bathroom scale taken to the Moon, because the scale would still divide by Earth's g.