Kinetic Energy Calculator
Instantly calculate the kinetic energy of any moving object using mass and velocity, based on the standard physics formula KE = ½mv².
Calculate Kinetic Energy
Kinetic energy is the energy an object possesses because of its motion. Enter a mass and velocity below to calculate it instantly, or follow the steps to work it out by hand.
How to Calculate It by Hand
Five steps using the standard kinetic energy formula
Find the Object’s Mass
Determine the mass of the moving object in kilograms. Convert from grams or pounds first if needed.
Find the Object’s Velocity
Determine the object’s speed in metres per second. Convert from km/h or mph first if that’s how it’s given.
Square the Velocity
Multiply the velocity by itself. This step matters most, since energy scales with the square of speed.
Apply the Formula
Multiply the mass by the squared velocity, then multiply the result by one half to get the kinetic energy in joules.
Convert Units If Needed
Divide by 1,000 to express large results in kilojoules, or by 1,000,000 for megajoules, depending on the scale of the object.
Kinetic Energy Calculator
Enter mass and velocity for an instant result
Kinetic Energy in Everyday Objects
Approximate kinetic energy for some common examples, to help put the numbers into perspective.
| Object | Mass | Velocity | Kinetic Energy |
|---|---|---|---|
| Walking person | 70 kg | 1.4 m/s | 69 J |
| Cyclist | 85 kg | 7 m/s | 2,083 J |
| Car at 30 mph | 1,200 kg | 13.4 m/s | 107,832 J |
| Car at 70 mph | 1,200 kg | 31.3 m/s | 588,714 J |
| Rifle bullet | 0.01 kg | 900 m/s | 4,050 J |
Kinetic Energy FAQ
Answers to the most frequently asked questions about calculating kinetic energy.
The formula for kinetic energy is KE equals one half multiplied by mass multiplied by velocity squared, written as KE = ½mv², where mass is in kilograms and velocity is in metres per second, giving a result in joules.
Kinetic energy is measured in joules (J) in the International System of Units. Larger quantities are often expressed in kilojoules (kJ) or megajoules (MJ) for convenience.
Because velocity is squared in the formula, doubling an object’s speed quadruples its kinetic energy, while doubling its mass only doubles the energy. This is why speed has such a dramatic effect on impact energy in collisions.
Kinetic energy depends on the square of velocity and describes the energy of motion, while momentum depends on velocity directly and describes the quantity of motion. They are related but distinct physical quantities with different formulas and units.