Free fall calculator
Enter the drop height for an object released from rest to get the fall time and impact speed.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter drop height and gravitational acceleration g.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
t = √(2h ÷ g), v = √(2 g h) = g × t, where h is the height and g the gravitational acceleration.
Example
Inputs: Drop height = 20 m, Gravitational acceleration g = 9.80665 m/s². Result: Fall time: 2.0196 s; Impact speed: 19.8057 m/s; Impact speed in km/h: 71.3005 km/h.
Limits and caveats
- Ignores air resistance, so results are less accurate for light objects or long drops.
- Assumes release from rest and constant g.
Questions about this tool
Do heavier objects fall faster?
Without air, every object falls with the same acceleration whatever its mass. The difference we see comes from air resistance.
How long does a 20 m fall take?
About 2.02 s with standard g, hitting at roughly 19.8 m/s, about 71 km/h.
Why is terminal velocity not shown?
Terminal velocity depends on shape, area and air density; this calculator assumes a fall in a vacuum.