Kinetic Energy Calculator
Calculate kinetic energy instantly in your browser — the published formula, worked locally with no data sent anywhere.
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What this tool does
Calculate kinetic energy instantly in your browser — the published formula, worked locally with no data sent anywhere. Translational kinetic energy of a non-rotating object. Because energy scales with v², doubling speed quadruples kinetic energy — the physics behind braking distances.
How to use the Kinetic Energy Calculator
- Enter or select mass in lb.
- Enter or select speed (mph).
- Read the calculated result; change any measurement to compare alternatives.
Formula
KE = ½·m·v², computed in SI: the mass (entered in lb, converted at 0.45359237 kg/lb) and speed (mph × 0.44704 = m/s) give energy in joules.
- mass
- Mass (lb, before metric conversion)
- speed
- Speed (mph)
Translational kinetic energy of a non-rotating object. Because energy scales with v², doubling speed quadruples kinetic energy — the physics behind braking distances.
Worked example
For kinetic energy calculator, the following measurements illustrate the exact method: Mass: 10; Speed (mph): 30.
Inputs
- Mass10 lb
- Speed (mph)30
Result
- Kinetic energy (J)407.92
- Kinetic energy (ft·lbf)300.86
- Mass (kg)4.54
- Speed (m/s)13.41
- Momentum at this speed (kg·m/s)60.83
Results explained
- Kinetic energy (J)
- Kinetic energy (J) from the formula above. Translational kinetic energy of a non-rotating object. Because energy scales with v², doubling speed quadruples kinetic energy — the physics behind braking distances.
- Kinetic energy (ft·lbf)
- Kinetic energy (ft·lbf) from the formula above. Translational kinetic energy of a non-rotating object. Because energy scales with v², doubling speed quadruples kinetic energy — the physics behind braking distances.
- Mass (kg)
- Mass (kg) from the formula above. Translational kinetic energy of a non-rotating object. Because energy scales with v², doubling speed quadruples kinetic energy — the physics behind braking distances.
- Speed (m/s)
- Speed (m/s) from the formula above. Translational kinetic energy of a non-rotating object. Because energy scales with v², doubling speed quadruples kinetic energy — the physics behind braking distances.
- Momentum at this speed (kg·m/s)
- Momentum at this speed (kg·m/s) from the formula above. Translational kinetic energy of a non-rotating object. Because energy scales with v², doubling speed quadruples kinetic energy — the physics behind braking distances.
Frequently asked questions
KE = ½·m·v², computed in SI: the mass (entered in lb, converted at 0.45359237 kg/lb) and speed (mph × 0.44704 = m/s) give energy in joules.
Translational kinetic energy of a non-rotating object. Because energy scales with v², doubling speed quadruples kinetic energy — the physics behind braking distances.
Every field is labelled with its unit — enter values in exactly the labelled unit and read the result in the labelled output unit. Fields with a unit symbol also support the site-wide imperial/metric switch, which converts before the formula runs.
It uses double-precision arithmetic and the published constants and formulas named on this page. The last displayed digit may be rounded, and real conditions can differ from the idealized model described in the assumptions.
Yes. Every calculation runs entirely in your browser; nothing you enter is uploaded, stored or shared.