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Kinetic Energy Calculator
Calculate kinetic energy from mass and speed, gravitational potential energy from height, or solve speed from a known kinetic energy. Choose the zero-height reference and gravity used for the estimate.
How do you calculate kinetic energy?
Kinetic energy is one half of mass times speed squared: KE = ½mv². Gravitational potential energy relative to a chosen height is PE = mgh. For example, a 2 kg object moving at 3 m/s has 9 J of kinetic energy. The total shown is the sum of these idealized values, not a prediction that includes friction or other losses.
Frequently asked questions
How do you calculate kinetic energy?
Kinetic energy is one half of mass times speed squared: KE = ½mv². Gravitational potential energy relative to a chosen height is PE = mgh. For example, a 2 kg object moving at 3 m/s has 9 J of kinetic energy. The total shown is the sum of these idealized values, not a prediction that includes friction or other losses.
Are my values uploaded?
No. The calculation runs locally in this browser; the values are not uploaded or saved.
Can I find speed from kinetic energy?
Yes. Select “Solve speed from kinetic energy,” then enter a positive mass and a kinetic-energy value of zero or greater. The calculator uses v = √(2KE/m).
Why can potential energy be negative?
Potential energy is measured relative to a reference height that you choose. A position below that zero level has negative mgh; this does not mean the object has negative mass or that kinetic energy is negative.
Does total mechanical energy include energy losses?
No. It is the sum of kinetic and gravitational potential energy only. Friction, air resistance, rotation, deformation and other energy transfers are not modeled.