⛰️ Potential Energy Calculator (PE = mgh)
Find gravitational potential energy from mass, gravity and height (PE = mgh), or solve for any of them.
Potential energy PE
490.332 J
Gravitational potential energy PE = m·g·h. g = 9.80665 m/s² on Earth (editable). 🔒 Computed in your browser.
How the potential energy calculator (pe = mgh) works
Gravitational potential energy near a surface is PE = mgh, where m is mass, g the gravitational field strength (9.8 m/s² on Earth) and h the height above a reference. Enter any three of the four and the tool solves for the last. Only differences in PE are physically meaningful, so the answer depends on where you set the zero, raising or lowering the reference level simply shifts every value by the same amount.
Potential energy is relative to a chosen zero height, only changes in PE matter physically. Change g to work on the Moon or Mars.
Frequently asked questions
How do I calculate gravitational potential energy?
PE = mgh. A 5 kg mass raised 10 m on Earth gains 5 × 9.8 × 10 = 490 J. Enter mass, gravity and height to compute it.
What is the reference point for height?
Any level you choose, PE is measured relative to it. Physics only depends on changes in height, so pick a convenient zero (often the ground or table).
How does potential energy convert to kinetic energy?
As an object falls, PE converts to KE. Ignoring air resistance, mgh at the top equals ½mv² at the bottom, giving v = √(2gh).
What units does PE = mgh use?
Joules (J), with mass in kg, g in m/s² and height in metres.
Does potential energy depend on the path taken?
No, gravitational PE depends only on the vertical height change, not the route. Gravity is a conservative force.
Worked example: lifting a box
Lifting a 15 kg box 2 m up on Earth gives PE = mgh = 15 × 9.81 × 2 ≈ 294 J of stored gravitational energy, equal to the work done against gravity.
Does PE = mgh work at large heights?
Only near a planet’s surface, where g is roughly constant. For satellites or space travel, gravity weakens with altitude and you need the general form U = −GMm/r instead.
Can potential energy be negative?
Yes, if an object sits below your chosen zero height, its PE = mgh comes out negative. Because only differences in PE matter physically, a negative value simply means the object is lower than the reference level.
What is gravitational field strength?
The value g (about 9.8 N/kg on Earth) is the gravitational field strength, the force per kilogram, and it numerically equals the free-fall acceleration. It appears directly in PE = mgh and is smaller on the Moon or Mars.