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
Kinetic energy (J)
300000
Kinetic energy (kJ)
300.00
Potential energy (J)
0
Total mechanical energy (J)
300000
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter mass (kg).
- 2Enter speed (m/s).
- 3Enter height (m).
- 4Read your kinetic energy (j) on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Kinetic energy scales with the square of speed — double the speed, quadruple the energy. That's why crash forces climb so fast.
Worked example
Using the values the calculator loads with:
Inputs
- Mass: 1500 kg
- Speed: 20 m/s
- Height: 0 m
Results
- Kinetic energy (J): 300,000
- Kinetic energy (kJ): 300
- Potential energy (J): 0
- Total mechanical energy (J): 300,000
What each field means
Inputs
- Mass (kg)
- The mass used in the calculation, measured in kg. Starts at 1500 kg so you have a working example on load.
- Speed (m/s)
- The speed used in the calculation, measured in m/s. Starts at 20 m/s so you have a working example on load.
- Height (m)
- The height used in the calculation, measured in m. Starts at 0 m so you have a working example on load.
Results
- Kinetic energy (J)
- 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.
- Kinetic energy (kJ)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Potential energy (J)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total mechanical 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 kinetic & potential energy calculator work?
Kinetic energy scales with the square of speed — double the speed, quadruple the energy. That's why crash forces climb so fast. The underlying maths is: KE = ½mv²; PE = mgh
What do I need to enter?
3 values: mass, speed, and height. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the kinetic energy (j) 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). Kinetic Energy Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/kinetic-energy
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/kinetic-energy" target="_blank" rel="noopener">Kinetic Energy Calculator — RevenueLab</a> (2026).</p>
Source: [Kinetic Energy Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/kinetic-energy) (2026).