Free Fall Calculator
The free fall calculator solves any falling-object problem in seconds, finding the height an object drops, the time it takes to land, and its final velocity at impact. Enter what you know and it works out the rest using the standard kinematic equations.
Free fall is the motion of an object pulled by gravity alone, with air resistance ignored. The tool applies h = ½gt², t = √(2h/g), v = gt, and v = √(2gh), so it suits physics homework, lab checks, and quick what-if estimates. You can also switch the gravitational acceleration from Earth to other worlds, comparing the Moon's gentle 1.62 m/s² with Jupiter's powerful 24.79 m/s².
How to Use the Free Fall Calculator
Choose a solve mode
Select the tab for the variable you want: Height (h), Time (t), or Velocity (v). The input fields update to match.
Set the gravity
Pick a planet or celestial body from the dropdown to load its gravitational acceleration, or choose Custom to type your own g value.
Enter a known value
Type the value you already have and choose its unit. In Height and Velocity modes you can enter either of two inputs — the other clears automatically.
Read the results
Results appear as you type, showing the formula with your values, the primary answer, and all three variables (h, t, v) at once. Scroll down for unit conversions and a height comparison with famous landmarks.
Solve mode guide
- Height mode — enter time or final velocity to find the distance fallen.
- Time mode — enter height to find how long the fall takes.
- Velocity mode — enter height or time to find the impact speed.
Features
Three Solve Modes
Switch between solving for height, time, or final velocity with a single click, and the input fields adapt to match.
Multi-Planet Support
Compare free fall across 8 celestial bodies — Earth, Moon, Mars, Venus, Jupiter, Saturn, Mercury, and the Sun — each with its real gravity.
Custom Gravity
Choose Custom to enter any gravitational acceleration value for hypothetical or specialized scenarios.
Flexible Units
Enter and read results in height (m, ft, cm, km, in, yd, mi), time (s, ms, min), and velocity (m/s, km/h, mph, ft/s).
Real-Time Results
Answers update instantly as you type — no submit button, no waiting.
Live Formula Display
See the exact equation with your actual values substituted in, making the physics easy to follow and verify.
Full Conversion Table
Every result is converted to all available units, grouped by height, time, and velocity for quick reference.
Height Comparison
A computed height is shown against landmarks like the Statue of Liberty, Eiffel Tower, Burj Khalifa, and Mount Everest for an intuitive sense of scale.
Frequently Asked Questions
How do you calculate free fall time?
Time to fall a given height comes from t = √(2h/g), where h is the drop height and g is the gravitational acceleration. Switch to Time mode, enter the height, and the calculator returns the fall time along with the resulting velocity.
What is the formula for free fall velocity?
Impact velocity from a known height is v = √(2gh), and velocity after a given time is v = gt. In Velocity mode you can enter either the height or the time to get the final speed.
Does mass affect free fall speed?
No. In ideal free fall every object accelerates at the same rate regardless of mass, which is why a feather and a hammer fall together in a vacuum. Mass only matters once air resistance is involved, which this calculator does not model.
What is gravitational acceleration (g)?
Gravitational acceleration is the rate at which a falling object speeds up. On Earth it is about 9.807 m/s², but it varies by world — roughly 1.62 m/s² on the Moon and 24.79 m/s² on Jupiter. Pick a planet from the dropdown to load its value automatically.
Does this calculator account for air resistance?
No. It uses the idealized free fall equations without drag. For short falls and standard physics problems these results are accurate, but for long falls or objects with large surface areas, real-world air resistance would lower the actual velocity.
Can I calculate free fall on other planets?
Yes. Select any of the 8 preset bodies from the dropdown, or choose Custom to enter any gravitational acceleration. This is handy for physics assignments, space-science comparisons, and exploring how fast objects fall elsewhere.
Is my data saved or sent anywhere?
No. Every calculation happens entirely in your browser. Nothing you enter is uploaded or stored on any server.
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