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Gravitational Potential Energy Calculator (mgh)

Use this gravitational potential energy calculator to find the change in stored gravitational energy from an object’s mass, vertical height, and local gravity. It returns energy in joules, compares the same setup on Earth, the Moon, and Mars, and shows the ideal fall-time and speed connection when air resistance is ignored.

Methodology. Every result is calculated locally in your browser with ΔPE = mgh. This near-surface model uses a constant gravity value and measures a change in height from the reference level you choose.

A learning and estimation model, not an impact-safety calculation. The energy value does not predict stopping force, damage, or injury. Those depend on stopping distance, materials, shape, impact angle, and other conditions not entered here.

Gravitational Potential Energy Calculator

Live
kg
Use mass, not weight.
m
Measure from one consistent reference level.
CHANGE IN GRAVITATIONAL POTENTIAL ENERGY
490.33 J
5 kg raised 10 m on Earth
Weight at this gravity49.03 NForce from mass × gravity
Ideal fall speed14.00 m/sFrom this height; no air resistance
Ideal fall time1.43 sFrom rest; no air resistance
Ready
Assumptions: constant gravity near the selected surface; energy is relative to the chosen reference height. Values update as you type.

What the result means

Gravitational potential energy is energy associated with relative height in an object–planet system. A positive result here means the object has gained energy because it is higher than the chosen reference level. In a no-loss idealization, that energy can convert into motion as the object falls. To calculate that moving energy directly from mass and speed, use the Kinetic Energy Calculator.

The formula

ΔPE = m × g × Δh
SymbolMeaningSI unit
ΔPEChange in gravitational potential energyjoule (J)
mMasskilogram (kg)
gGravitational accelerationm/s²
ΔhVertical change in heightmeter (m)
Worked example

For a 5 kg object raised 10 m on Earth, ΔPE = 5 × 9.80665 × 10 = 490.33 J. This is a change relative to the selected reference level, not an absolute universal energy value.

Check the calculation by hand

For a quick independent check, multiply mass by the selected gravity and the vertical height change. Keep the inputs in kilograms, meters, and m/s² so the result is in joules.

Manual check for the default example

5 kg × 9.80665 m/s² × 10 m = 490.3325 kg·m²/s² = 490.33 J after rounding to two decimal places.

For longer expressions or a repeatable classroom check, enter 5 × 9.80665 × 10 in the Numeros Scientific Calculator. The energy calculator remains the faster choice when you also want the reference-level guidance, planet comparison, and ideal free-fall connection.

Compare the same mass and height on Earth, the Moon, and Mars

Mass and height are held constant below. Only gravity changes, so the energy changes in direct proportion to g. This comparison is useful for classroom problems; the simple mgh approximation is intended for height changes that are small relative to a planet’s radius.

LocationGravityPotential energyvs. Earth

How height and mass affect energy

Potential energy is linear in both mass and vertical height. Doubling the mass doubles the energy. Doubling the height also doubles the energy. That is different from the kinetic-energy relationship, where speed is squared.

ScenarioMassHeightEnergy at selected gravity

Potential energy and free fall: the connection

When an object drops and losses such as air resistance are negligible, its lost gravitational potential energy becomes kinetic energy. The ideal final speed depends on height and gravity, while mass cancels from the speed equation. You can model the corresponding time and final speed in the Free Fall Calculator; use the Acceleration Calculator when you need a broader constant-acceleration calculation.

The calculator treats the vertical separation from your chosen reference as Δh. The arrow shows a change in height, not a predicted path or impact.

Why the reference level matters

Potential energy is measured relative to a chosen zero level. You may choose the ground, a laboratory bench, or the bottom of a ramp; the important rule is to measure every compared height from the same reference. Changing the zero changes the reported value but does not change the physical energy difference between two positions.

When the mgh formula is appropriate

The mgh expression is a near-surface constant-gravity approximation. It works well for typical laboratory, building, and classroom height changes. It is not the right model for large astronomical distances, orbital mechanics, or situations where gravity changes materially with distance. The formula gives an energy change; it does not account for friction, drag, deformation, heat, or real-world stopping force.

Step-by-step guide

  1. Enter mass in kilograms. Do not enter weight in newtons in the mass field.
  2. Enter the vertical change in height. Use one consistent reference level for every comparison.
  3. Select Earth, Moon, or Mars gravity. The calculator uses the selected constant surface value.
  4. Read the energy in joules. Use the comparisons and the related calculators when you need motion or acceleration, not just stored energy.

Common mistakes

Using weight as if it were mass. The input is mass in kilograms. Weight is a force in newtons and already includes gravity.
Mixing reference levels. If one height is measured from the floor and another from a table, the difference will be meaningless unless both use the same zero level.
Treating joules as an impact-force answer. Energy alone cannot determine the force of a collision. The stopping distance and time are essential.

Frequently asked questions

What is gravitational potential energy?

It is energy associated with relative position in a gravitational field. Near a planet’s surface, the change in energy for a vertical height change is ΔPE = mgh.

Is gravitational potential energy always positive?

No. A positive or negative change depends on your sign convention and reference level. This calculator is designed for a positive magnitude of energy gained by raising an object through a positive height.

Does the path change the mgh result?

For this near-surface model, only the vertical change in height matters. A ramp, stairs, and vertical lift give the same change in potential energy when the start and end heights are the same.

How does potential energy become kinetic energy?

If drag and friction are negligible, a drop converts lost gravitational potential energy into kinetic energy. In real conditions, some energy may also transfer to heat, sound, deformation, or other effects.

Why is this calculator not for orbits or large altitudes?

Over very large distances, gravity is not constant. The simple mgh approximation should be replaced with a gravitational model that accounts for changing distance from the planet.

Sources

Related calculators

Use these tools when the next question is about motion, force, or a different physics quantity: