Example 1
A 8.00 kg backpack tossed onto a shelf 1.8 m up.
Potential Energy Calculator
Type mass m [kg] and height h [m]. The calculator computes Ep = m g h with g = 9.81 m/s²: 8 kg at 1.8 m is about 141 J, and 60 kg at 2 m is about 1.18 kJ. Measure h from your own zero.
Result
Mass and Height (m). Potential energy shows up here.
How it works
Gravitational potential energy is mass times g times height: Ep = m g h. An 8 kg pack on a 1.8 m shelf is 8 × 9.81 × 1.8 ≈ 141 J. A 60 kg person lifted 2 m is about 1177 J, the 1.18 kJ order on the page. 1 kg at 1 m is 9.81 J. 10 kg at 0.5 m is 49.05 J. A 0.80 kg volume at 1.5 m is about 11.8 J. A 12 kg bucket at 6 m is about 706 J.
A 3 kg pot at 12 m is about 353 J. An 80 kg skier and 300 m of vertical is about 235 kJ. A 50,000 kg tank at 30 m is about 14.7 MJ. A 400 kg car at 30 m is about 118 kJ. What counts is the difference from your zero: floor, ground, bottom of the slope, not sea level.
Mass is in kilograms, h in meters. g is built in, 9.81 m/s², no field. The result is in joules, 1 J = 1 kg·m²/s². A comma and a period are the same h: 1,8 and 1.8. Typed 0 kg or 0 m gives Ep = 0. Both fields need a number before 141 can appear. A negative h means below your zero if the problem uses that sign.
Ek = ½ m v² is on the neighbouring page: speed there, height here. When lifting, work W = F·s is often close to Ep if F ≈ m g. A vertical throw computes height from v, not from a typed h. Elastic energy ½ k x² is another calculator.
The model is terrestrial. On the Moon g is different and this calculator does not ask for it. The US switch may show pounds on the mass label. The header symbol does not lift the pack.
Type 8 and 1.8, click Calculate, and match about 141 J. Then 60 and 2. Treat h as a difference from the floor, not as height above the sea.
Energy of motion: Ek. Height in a throw: vertical throw.
How to use
- In the first field enter mass in kilograms, for example 8 or 60.
- In the second field enter h from your reference in meters, for example 1.8. That is a difference from the floor, not height above sea level.
- Click Calculate. The calculator multiplies m, g = 9.81, and h. 8 kg and 1.8 m give about 141 J.
- Typed 0 gives Ep = 0. Both fields need a number. You do not type g: it is 9.81.
- Energy of motion is on Ek. Lifting work is on W = F·s. Here it stays m g h.
Formula
Ep = m · g · h
m is the mass, h is the height above your reference point in meters, and g = 9.81 m/s². The result is in joules: 1 J = 1 kg·m²/s².
Ep, m, g, and h above the floor
Potential energy here is Ep = m g h. 8 kg at 1.8 m is about 141 J. Measure h from your floor, not from sea level.
- Ep
- Potential energy [J]. 60 kg lifted 2 m is about 1177 J, order 1.18 kJ. 1 kg at 1 m is 9.81 J.
- m
- Mass [kg]. A 0 gives Ep = 0. 12 kg at 6 m is about 706 J.
- g
- Built-in 9.81 m/s², no field. Earth model. The calculator does not ask for the Moon.
- h
- Height from your zero [m]. 1.8 m or 2 m. Not elevation above sea level.
Real-life examples
Example 2
60.0 kg pressed out at arm’s length, 2 m above the platform.
Example 3
A 0.80 kg volume on a 1.5 m shelf.
Example 4
A 12.0 kg bucket hoisted 6 m up the scaffold.
Example 5
The tank holds 50000 kg of water, 30 m above the ground.
Example 6
A 400 kg roller coaster car atop the 30 m lift hill: the whole ride’s budget.
Example 7
A 3.00 kg pot on a fourth-floor sill (12 m).
Example 8
A 80.0 kg skier at the top of a run with 300 m of vertical.
Example 9
A cab with passengers, 600 kg total, rides up 40 m.
Example 10
A 4.00 kg cat stuck on a branch 5 m above the lawn.
Example 11
A 5.00 kg grocery bag lifted onto a 0.9 m countertop.
Frequently asked questions
How much Ep at 8 kg and 1.8 m?
Energy is about 141 J. You compute 8 × 9.81 × 1.8. That is a person on a step, not a truck.
How much at 60 kg and 2 m?
You get about 1177 J, or 1.18 kJ. Sixty kilograms lifted two metres.
Which units do I type?
Mass m [kg], height h [m]. Result Ep [J]. g is built in: 9.81 m/s², with no field.
Is h height above sea level?
No. h is from your reference: floor, bench, ditch bottom. Sea level does not enter the formula.
Where is g in the form?
There is no field. The calculator multiplies by 9.81 m/s². This is an Earth model, not a lunar one.
How is Ep different from Ek?
Ep depends on height. Ek = ½ m v² depends on speed. Same joules, different formula.
How much at 12 kg and 6 m?
Energy is about 706 J. Twelve kilograms at six metres.
Does a comma in 1.8 work?
Yes. 1.8 and 1,8 are the same h [m]. A comma and a period mean the same value.
Where is work W = F s?
On the work-of-a-force page. For a steady weight F ≈ m g and s = h, that work is often close to this Ep, but the fields differ.
How much at 1 kg and 1 m?
Energy is 9.81 J. One kilogram at one metre is simply g in joules.
Knowledge sources
The formula is the school one. Units follow SI; NIST SP 330 and BIPM define the measures, not your result.
Page updated in 2026.