MihsabaHow to use
Classical kinetic energy equals one half mass times speed squared. Solve for any variable while the calculator converts inputs through SI units internally.
- Choose energy, mass or speed as the unknown.
- Enter the two known values and their units.
- Calculate the result and its SI value.
How it is calculated
KE=½mv²; m=2KE÷v²; v=√(2KE÷m)
Example
Example: a 1500 kg car at 20 m/s has 300,000 J = 300 kJ of kinetic energy.
Important notes
This is the classical formula, not a relativistic one; speeds near the speed of light require relativistic mechanics.
Frequently asked questions
Why does doubling speed quadruple energy?
Because speed is squared in KE=½mv².
Can kinetic energy be negative?
Not in this classical formula for positive mass; the calculator uses non-negative speed magnitude.
Is this calculator free?
Yes. It is free to use and requires no account.