Energy Calculator
Calculate Kinetic Energy (½mv²) and Potential Energy (mgh) of objects.
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Quick Tip
Enter the mass in kilograms.
About This Tool
Why use Energy Calculator?
This calculator works out the two mechanical energies of an object: kinetic energy from motion, KE = ½mv², and potential energy from height, PE = mgh, using g = 9.81 m/s². It adds them into a total and also converts the kinetic energy into food calories.
A 1,000 kg car at 20 m/s carries ½ × 1000 × 400 = 200,000 joules. Because velocity is squared, doubling the speed quadruples the energy — which is why stopping distances grow so sharply with speed. Lifting that same car 10 metres stores 1000 × 9.81 × 10 = 98,100 joules of potential energy.
Key Benefits
Kinetic and potential together
Both forms are shown alongside their total, which is the quantity conserved in an ideal system.
Shows the effect of squaring velocity
Change the speed and the kinetic energy moves with its square, making the risk of higher speeds obvious.
Everyday comparison
The kilocalorie conversion (1 kcal = 4,184 J) puts the joule figure into familiar terms.
How to use Energy Calculator
- 1
Enter the mass in kilograms.
- 2
Enter the velocity in m/s for kinetic energy.
- 3
Enter the height in metres for potential energy.
- 4
Read each energy separately and the total mechanical energy, in joules.
Best use cases
Solve kinetic and potential energy problems in physics homework.
Compare the energy of a vehicle at two different speeds.
Work out the energy stored by lifting a load.
Estimate the impact energy involved in a fall.
Energy Calculator FAQs
What are the kinetic and potential energy formulas?
KE = ½mv² and PE = mgh, where m is mass in kg, v is velocity in m/s, g is 9.81 m/s² and h is height in metres. Both results are in joules.
Why does doubling speed quadruple kinetic energy?
Velocity is squared in the formula. At twice the speed, v² is four times larger, so the energy — and the work needed to stop the object — is four times greater.
How many joules are in a calorie?
One food calorie (kilocalorie) is 4,184 joules. A 500 kJ figure is about 120 kcal.
What is total mechanical energy?
Kinetic plus potential energy. Without friction it stays constant, which is why a pendulum trades height for speed and back again.
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