Kinetic Energy Calculator
Calculate the kinetic energy of a moving object from its mass and velocity.
Assumptions used in this calculation
- Non-relativistic speeds: Uses the classical (Newtonian) formula, valid at everyday speeds, far below the speed of light where relativistic corrections would apply.
About this calculator
Kinetic energy grows with the square of velocity rather than in direct proportion to it, a detail that's easy to overlook when estimating stopping distances, collision forces, or how much energy a moving object actually carries, since doubling speed doesn't just double the energy, it quadruples it, which manual back-of-envelope estimates often get wrong. This calculator applies KE = ½mv² directly, taking an object's mass in kilograms and its velocity in metres per second to return kinetic energy in joules. It's useful for physics coursework, estimating the energy involved in a vehicle collision or a falling object's impact, comparing how much more damaging a fast-moving object is than a slightly slower one, or sanity-checking a hand calculation, since the squared-velocity term is the step most commonly miscalculated when working the formula by hand.
Worked example
10kg object at 5 m/s
Result: 125 J
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