Weight Calculator
Calculate weight (the force of gravity on an object) from its mass and the local gravitational acceleration.
How to use the Weight Calculator
- Enter your inputs into the Weight Calculator above.
- Results update instantly as you type — no submit button needed.
- Adjust any value to see how the result changes in real time.
The weight formula
W = m × g
m is mass in kg, g is gravitational acceleration (9.81 m/s² on Earth surface). Result is in Newtons (N). To convert: 1 N ≈ 0.225 lb-force.
Worked example
A 70 kg person on Earth: W = 70 × 9.81 = 687 N. Same person on the Moon (g = 1.62): W = 70 × 1.62 = 113 N — about 1/6 of Earth weight. On Mars (g = 3.71): W = 260 N.
Frequently asked questions
Why does weight change on different planets?
Because gravitational pull depends on the planet's mass and your distance from its center. Mass stays the same; weight (the force) varies with where you are.
What is g on different surfaces?
Earth surface: 9.81 m/s². Moon: 1.62. Mars: 3.71. Jupiter "surface" (cloud tops): 24.79. Sun: 274 — you couldn't stand on the Sun even ignoring the temperature.
How does altitude affect weight?
Very slightly. At 10,000 m above sea level, g is about 9.77 m/s² (vs. 9.81 at sea level). The 0.4% difference is negligible for everyday purposes.