Gravitational Potential Energy (PE = m·g·h)

Energy stored in an object lifted to a height. Enter mass, height, and (optionally) the gravity of another planet.

Result

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How to use this calculator

Enter mass in kg.
Enter height in metres above the chosen zero (ground level is the usual choice).
Optionally change g for a different planet.
Read PE in joules. The breakdown shows free-fall impact speed if released from rest.

About this calculator

Gravitational potential energy is the energy stored in an object's vertical position relative to a reference level — typically the ground or some chosen zero. Lifting a 70 kg adult one storey (≈ 3 m) stores about 2 060 J. That is the energy that returns as kinetic energy on the way down: ignoring air resistance, the object hits the ground at v = √(2gh). Because g varies with location and especially with which planet you are on, this calculator lets you change g — useful for engineering problems on the Moon (1.62 m/s²) or Mars (3.71 m/s²). PE is conventionally measured from a chosen reference height; only changes in PE are physically meaningful.

Frequently asked

Where is the "zero" of potential energy?+

Wherever you choose. Only differences in PE matter physically. Pick the most convenient reference — usually the floor for engineering, infinity for orbital problems.

Does this account for changing g with altitude?+

Not at this scale — the formula assumes g is constant. That is accurate for heights well under 1% of Earth's radius (≈ 64 km). For satellites, use U = −G·M·m/r.

How does PE convert to KE?+

In a frictionless free fall, all PE converts to KE: ½·m·v² = m·g·h, so v = √(2gh). The breakdown above shows this impact speed.

How much PE is in a single floor of building?+

A 70 kg person lifted one floor (~3 m) on Earth gains ~2 060 J ≈ 0.49 kcal. A 6-storey climb is roughly the energy of one tablespoon of salad oil — explains why stairs are surprisingly easy in calorie terms.

Why use 9.80665?+

That's the international standard value of gravity at Earth's surface. Locally it varies from ~9.78 (equator) to ~9.83 (poles).