Energy & Power Calculator
Convert between energy and power over time, and work out kinetic energy, potential energy, and work done. Calculates in your browser.
Show the math
Kinetic energy depends on speed; gravitational potential energy on height:
KE = ½mv² · PE = mgh · P = E ÷ t
Energy is in joules and power in watts, using g = 9.80665 m/s². All math runs in your browser.
What this does
An energy & power calculator converts between energy and power over time, and works out kinetic energy, potential energy, and work done.
How to use it
- Pick the quantity to find.
- Enter the known values.
- Read the result.
- Switch units as needed.
How it works
Power is energy per unit time, so a 100 W device for an hour uses 100 Wh. Kinetic energy depends on speed squared; potential energy near Earth on height.
P = E ÷ t; KE = ½mv²; PE = mgh
Understanding your result
The distinction to hold onto is that power is the rate and energy is the total: a high-wattage device is only expensive if it runs long enough to rack up energy. Kinetic energy scales with speed squared, so doubling speed quadruples the energy, which is why impacts and braking distances grow so sharply, and potential energy near Earth depends only on height and mass.
Example
A 100 W bulb run for 2 hours uses 200 Wh of energy.
Sources & methodology
Last updated .
Frequently asked questions
How are energy and power related?
Power is energy per unit time: P = E ÷ t. So energy is E = P × t — a 100 W device for 1 hour uses 100 Wh.
What is kinetic energy?
Kinetic energy is ½mv², the energy of a moving mass. Potential energy near Earth is mgh.
Is my data stored?
No. Everything is calculated locally in your browser.
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