Free fall calculator
Work out the fall time, impact speed and height in free fall, on Earth, the Moon or Mars, with a table of position and speed at each moment.
How to useFree fall: height, time and speed
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Free fall calculator: what it is for
Enter the height, the fall time or the impact speed and choose the gravity (Earth, the school value of 10 m/s², the Moon, Mars, Jupiter, Mercury or Venus). The calculator uses h = g·t²/2 and v = g·t and builds a table with the distance fallen, the remaining height and the speed at each moment.
The calculations run in your browser and ignore air resistance, as in high school physics problems.
How to use
- Choose the value you know.
- Type the value and choose the gravity.
- See the results and the table.
When to use it
- Solving free fall problems.
- Estimating the depth of a well from the time a stone takes to fall.
- Comparing the gravity of other worlds.
Frequently asked questions
What are the free fall formulas?
Without air resistance and starting from rest: h = g·t²/2, v = g·t and v² = 2·g·h. On Earth g ≈ 9.8 m/s² is used, and school exercises often use g = 10 m/s².
Does a heavier object fall faster?
In a vacuum, no: all bodies fall with the same acceleration, as Galileo showed. In air, resistance makes light, wide objects such as a feather fall more slowly. The calculator ignores air resistance.
What about on the Moon?
The Moon's gravity is about 1.62 m/s², roughly one sixth of Earth's. A 10 m fall takes about 3.5 s on the Moon versus 1.4 s on Earth.