What is it?
The Kinetic & Potential Energy Calculator works out Kinetic energy from mass and speed, Potential energy from height, and the Total energy.
Who is it for?
Physics students, road-safety educators and anyone curious about crash energy and falls.
How to use it
Enter the Mass, Speed (choose Speed in km/h, m/s or mph) and Height. The answer appears as you type; there is no Calculate button. Tap Copy result to copy it, or Share on WhatsApp to send it.
The formulas
KE = ½ m v², PE = m g h (g = 9.80665 m/s²).
Why speed matters in a crash
Doubling speed gives four times the energy, which is why speed matters so much in a crash. The result Same energy as falling from shows the equivalent fall: a car at 60 km/h has the same energy as falling from about 14 m, a four-storey building. At 120 km/h it is about 57 m.
Speed after a fall
Speed after falling that height ignores air resistance: v = √(2gh). A fall from 5 m reaches about 36 km/h.
Units
Energy is in joules (J); 1 kJ = 1,000 J. Food calories: 1 kcal = 4,184 J.
Worked example
A 1,000 kg car at 72 km/h (20 m/s): KE = ½ × 1000 × 20² = 200,000 J (200 kJ).
Errors and how to fix them
- Very large energy: check speed unit (km/h vs m/s).
Open the tool: Kinetic & Potential Energy Calculator
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