Rex says
The fast lane for the math you almost remember from school. Type the numbers, get the answer, move on with your day.
Try a scenario
Click to load — tweak from there.Inputs
Result
Fall time (s)
1.43
Impact speed (m/s)
14.01
Impact speed (km/h)
50.4
Kinetic energy (J)
98.1
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter drop height (m).
- 2Enter mass (kg).
- 3Enter gravity (m/s²).
- 4Read your fall time (s) on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
How fast is something moving after falling a given height, and how long does it take? Vacuum assumption — real drops slow down from drag.
Worked example
Using the values the calculator loads with:
Inputs
- Drop height: 10 m
- Mass: 1 kg
- Gravity: 9.81 m/s²
Results
- Fall time (s): 1.43
- Impact speed (m/s): 14.01
- Impact speed (km/h): 50.4
- Kinetic energy (J): 98.1
What each field means
Inputs
- Drop height (m)
- The drop height used in the calculation, measured in m. Starts at 10 m so you have a working example on load.
- Mass (kg)
- The mass used in the calculation, measured in kg. Starts at 1 kg so you have a working example on load.
- Gravity (m/s²)
- The gravity used in the calculation, measured in m/s². Starts at 9.81 m/s² so you have a working example on load.
Results
- Fall time (s)
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Impact speed (m/s)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Impact speed (km/h)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Kinetic energy (J)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the free fall distance & speed calculator work?
How fast is something moving after falling a given height, and how long does it take? Vacuum assumption — real drops slow down from drag. The underlying maths is: t = √(2h ÷ g); v = g × t
What do I need to enter?
3 values: drop height, mass, and gravity. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the fall time (s) result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are rounded for display; the underlying calculation keeps full precision.
Who is this tool for?
It's built for students, developers, and anyone who needs the answer right now without setting up a spreadsheet.
Accuracy and limitations
- Results are rounded for display; the underlying calculation keeps full precision.
- Very large or very small inputs may hit floating-point limits in the browser.
- Inputs outside the accepted range are clamped rather than rejected.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Free Fall Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/free-fall
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/free-fall" target="_blank" rel="noopener">Free Fall Calculator — RevenueLab</a> (2026).</p>
Source: [Free Fall Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/free-fall) (2026).