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Potential Energy Calculator

Find how much energy is stored in an object raised off the ground

Input Parameters

kg
m
m/s²

Gravitational potential energy is the energy an object possesses due to its position in a gravitational field. [1, 2, 3] It is the energy stored by lifting an object against the force of gravity. [1]

  • Energy of Position: The higher an object is, the more gravitational potential energy it has. [2, 4] This energy can be converted into kinetic energy if the object is allowed to fall. [4]
  • Weight: This is the force of gravity acting on an object (mass × gravity). It is distinct from potential energy. [5]

PE = mgh

Weight = mg

Enter parameters and click Calculate

About Potential Energy Calculator

The Energy of Position: The Ultimate Guide to Our Potential Energy Calculator

Energy is the currency of the universe. It flows, it transforms, but it is never lost. While we often think of energy in its most active form—the energy of motion, or kinetic energy—there is another, equally important form: **Potential Energy**. This is the silent, stored energy an object possesses not because of its movement, but because of its position or configuration within a system.

Think of a boulder perched at the edge of a cliff, a drawn archer's bow, or the water held back by a massive dam. In each case, there is immense energy waiting to be unleashed. This "energy of position" is what we call potential energy. It represents the *potential* to do work or to be converted into kinetic energy. Understanding and calculating it is fundamental to physics, engineering, and our understanding of the natural world.

Welcome to the definitive guide to this core concept. Our Potential Energy Calculator is a versatile tool designed to help you quantify the two most common forms of potential energy in classical mechanics: **Gravitational Potential Energy** and **Elastic Potential Energy**. This comprehensive article will not only guide you through the calculator's use but will also illuminate the principles behind each form of stored energy.

What is Potential Energy?

Potential energy is the stored energy of an object due to its position or state. It's the energy an object has because of its potential to move or change. For example, a ball held at a height has gravitational potential energy because it can fall due to gravity.

When you lift a box from the floor to a shelf, you do work against the conservative force of gravity. This work isn't lost; it's stored in the box as gravitational potential energy. When you compress a spring, you do work against the conservative elastic force. This work is stored in the spring as elastic potential energy. This stored energy can be fully recovered and converted back into other forms.

Part 1: Gravitational Potential Energy (GPE)

Gravitational Potential Energy is the energy an object possesses due to its vertical position in a gravitational field. The higher an object is lifted, the more work is done against gravity, and the more GPE it stores.

The GPE Formula

The formula for calculating GPE for an object near the surface of a planet is simple and elegant:

GPE = m * g * h
  • m is the **mass** of the object in kilograms (kg). A more massive object stores more energy at the same height.
  • g is the **acceleration due to gravity**. On the surface of the Earth, this is a constant value of approximately **9.81 m/s²**.
  • h is the **vertical height** of the object in meters (m), measured relative to a chosen "zero" point or reference level.

The choice of the zero level (h=0) is arbitrary. You can define it as the floor, the ground, or the top of a table. What matters for calculations is the *change* in height, and thus the *change* in potential energy. The energy itself is measured in **Joules (J)**.

GPE Worked Example: A Crane

A construction crane lifts a 1,200 kg steel beam to a height of 50 meters. How much gravitational potential energy has the beam gained?

  • Inputs: m = 1,200 kg, g = 9.81 m/s², h = 50 m.
  • Formula: `GPE = mgh`
  • Calculation: `GPE = 1200 * 9.81 * 50 = 588,600 J`.
  • Result: The beam has gained 588,600 Joules (or 588.6 kilojoules) of potential energy. This is the minimum amount of work the crane's motor had to do to lift the beam.

Part 2: Elastic Potential Energy (EPE)

Elastic Potential Energy is the energy stored in an elastic object (like a spring, rubber band, or bow) as a result of its deformation—being stretched or compressed. This energy is stored in the bonds between the atoms of the material.

The EPE Formula

The calculation of EPE is based on Hooke's Law and represents the work done to deform the object.

EPE = ½ * k * x²
  • k is the **spring constant**, a measure of the material's stiffness, in Newtons per meter (N/m). A higher `k` means a stiffer spring.
  • x is the **displacement** from the object's equilibrium (natural) position, in meters (m). This is the distance it has been stretched or compressed.

The most important feature here is the `x²` term. This means the energy stored is not linear. If you double the compression of a spring, you quadruple the stored energy. This non-linear relationship is key to the power of many elastic devices.

EPE Worked Example: A Pogo Stick

A pogo stick has a spring with a spring constant of 20,000 N/m. A 50 kg person compresses the spring by 15 cm when they land on it. How much energy is stored at maximum compression?

  • Inputs: k = 20,000 N/m, x = 15 cm = 0.15 m.
  • Formula: `EPE = ½kx²`
  • Calculation: `EPE = 0.5 * 20000 * (0.15)² = 10000 * 0.0225 = 225 J`.
  • Result: At the bottom of the bounce, 225 Joules of energy are stored in the spring, ready to launch the person back into the air.

How to Use the Potential Energy Calculator

Step 1: Select the Type of Potential Energy

Begin by choosing whether you want to calculate **Gravitational** or **Elastic** potential energy. This will configure the calculator with the correct formula and input fields.

Step 2: Enter the Required Variables

For Gravitational Potential Energy:

  • Enter the **Mass (m)** in kilograms.
  • Enter the **Vertical Height (h)** in meters.
  • The calculator uses the standard value for Earth's gravity (`g`), but this can be adjusted for other planets if desired.

For Elastic Potential Energy:
  • Enter the **Spring Constant (k)** in Newtons per meter.
  • Enter the **Displacement (x)** in meters.

Step 3: View the Result

The calculator will instantly provide the stored potential energy in **Joules (J)**.

The Principle of Conservation of Mechanical Energy

The true power of potential energy comes to life when we consider its relationship with kinetic energy. In a system where only conservative forces (like gravity and elastic forces) are doing work, the total mechanical energy remains constant.

Total Energy = PE + KE = Constant

This means `PE_initial + KE_initial = PE_final + KE_final`. This principle allows us to predict the motion of systems beautifully.

Consider a pendulum. At the top of its swing, its height `h` is maximum and its velocity is zero. It has maximum potential energy and zero kinetic energy. As it swings downwards, `h` decreases, so its PE converts into KE, and its velocity increases. At the very bottom of the swing, `h` is at its minimum and velocity is at its maximum. Here, it has minimum potential energy and maximum kinetic energy. The cycle then reverses as it swings up the other side.

Frequently Asked Questions (FAQ)

Q: Can potential energy be negative?

Yes, for gravitational potential energy. Since the zero height level is arbitrary, if an object moves below your chosen zero point (e.g., into a hole), its height `h` is negative, resulting in negative GPE. This is perfectly fine; only the *change* in potential energy is physically significant. Elastic potential energy, however, can never be negative, because both `k` and `x²` are always positive values.

Q: What about non-conservative forces like friction?

Our calculator and the simple conservation of energy principle assume an ideal system. In the real world, non-conservative forces like air resistance and friction are almost always present. These forces do "negative work," converting some of the mechanical energy into thermal energy (heat). This is why a bouncing ball eventually stops bouncing; on each bounce, some energy is lost to heat and sound, so it can't return to its original height.

Unlock the Stored Power of the Universe

Potential energy is a profound concept that illustrates the elegance and order of the physical world. It shows us that energy is a conserved quantity, elegantly shifting between stored potential and active motion.

Use our Potential Energy Calculator to explore these two fundamental forms of stored energy. Calculate the power stored in a hydroelectric dam, the launch energy of a slingshot, or simply build a deeper, more quantitative understanding of the energy that shapes every interaction in our lives.

Frequently Asked Questions

What is a Potential Energy Calculator?
A tool that calculates the stored energy of an object based on its position or configuration.
What are the main types of potential energy?
Gravitational, elastic, chemical, electrical, and nuclear potential energy.
How do I calculate gravitational potential energy?
PE = mgh, where m is mass (kg), g is gravity (9.81 m/s²), and h is height (m).
What units does this calculator use?
Standard SI units: joules (J) for energy, kilograms (kg) for mass, and meters (m) for height.
What's the reference point for potential energy?
It's arbitrary - we typically use the lowest point in the system or ground level as zero potential.
Can I calculate elastic potential energy?
Yes, using PE = ½kx² where k is spring constant and x is displacement from equilibrium.
Why is potential energy called 'potential'?
Because it represents energy that could potentially do work if released or converted.
How does height affect gravitational potential energy?
PE increases linearly with height - double the height means double the PE.
What's the potential energy at Earth's surface?
By convention, we often set PE=0 at surface level, but it depends on your reference point.
Can potential energy be negative?
Yes, if the reference point is above the object's position (common in astronomy).
How does mass affect potential energy?
PE is directly proportional to mass - double the mass means double the PE.
What's the relationship between potential and kinetic energy?
They can convert into each other, with total mechanical energy often remaining constant.
How do I calculate potential energy on other planets?
Use the same formula but substitute the planet's gravitational acceleration for g.
What's the potential energy of a spring?
PE = ½kx², maximum at maximum compression or extension, zero at equilibrium.
Why is the spring potential energy equation quadratic?
Because the force increases linearly with displacement (Hooke's Law), requiring more energy for each additional stretch.
How accurate are the calculator's results?
Accuracy depends on input precision and assuming ideal conditions (no air resistance, perfect springs, etc.).
Can I calculate chemical potential energy?
This calculator focuses on mechanical PE; chemical PE requires thermodynamic calculations.
What's the potential energy of an electron in an atom?
This involves quantum mechanics and isn't covered by classical potential energy formulas.
How does potential energy relate to work?
The change in PE equals the work done against the conservative force (like gravity or spring force).
What's the potential energy at infinite distance?
For gravitational systems, PE approaches zero as distance approaches infinity.
How do I calculate potential energy in a uniform electric field?
PE = qEd for charge q, field strength E, and distance d in field direction.
What's the potential energy of a dipole in an electric field?
PE = -pEcosθ where p is dipole moment and θ is angle between p and E.
How does potential energy relate to stability?
Objects tend toward positions of lower potential energy, with local minima representing stable equilibria.
What's the potential energy of water behind a dam?
PE = mgh where h is the height difference between water surface and turbine.
How do I calculate gravitational potential energy between two masses?
PE = -Gm₁m₂/r where G is gravitational constant and r is distance between centers.
Why is gravitational potential energy negative?
By convention, it's negative because it would take work to separate the masses to infinity (where PE=0).
What's the potential energy of a book on a shelf?
PE = mgh relative to the floor, where h is the shelf height.
How does potential energy change in orbits?
In circular orbits, total energy is constant but continuously converts between KE and PE.
What's the potential energy of a compressed gas?
This involves thermodynamic potentials and isn't calculated with simple mechanical formulas.
How do I calculate the potential energy of a pendulum?
PE = mgh where h is the vertical height difference from the lowest point.
What's the potential energy at Earth's center?
Theoretical minimum for Earth's gravity, but calculations require integration due to changing g.
How does potential energy relate to conservative forces?
Conservative forces (like gravity) have associated potential energy; non-conservative forces (like friction) don't.
What's the potential energy of a charged capacitor?
PE = ½CV² where C is capacitance and V is voltage difference.
How do I calculate potential energy in a non-uniform gravitational field?
Requires integration of F·dr over the path, as g changes with position.
What's the potential energy of a magnetic dipole?
PE = -μ·B where μ is magnetic moment and B is magnetic field.
How does potential energy appear in Schrödinger's equation?
As the V(x) term representing how potential energy varies with position in quantum systems.
What's the potential energy of an ideal gas?
Zero, because ideal gas molecules have no intermolecular forces (no potential energy).
How do I calculate potential energy in a hilly terrain?
PE = mgh where h is the elevation relative to your chosen reference point.
What's the potential energy of a stretched rubber band?
Complex to calculate exactly as rubber doesn't perfectly obey Hooke's Law.
How does potential energy relate to escape velocity?
Escape velocity is calculated by setting KE = |PE| at planet's surface.
What's the potential energy in a hydrogen atom?
PE = -ke²/r where k is Coulomb's constant, e is electron charge, and r is orbital radius.
How do I calculate potential energy in a binary star system?
PE = -Gm₁m₂/r where r is the distance between the stars.
What's the potential energy of a ball rolling down a ramp?
Initially mgh where h is ramp height, converting to kinetic energy as it rolls.
How does potential energy vary in a geosynchronous orbit?
Constant PE because altitude remains fixed relative to Earth's surface.
What's the potential energy of a bungee jumper?
Gravitational PE decreases while elastic PE increases during the fall.
How do I calculate potential energy in a Van der Waals interaction?
PE varies with distance as -A/r⁶ + B/r¹² where A and B are material constants.
What's the potential energy of a satellite in elliptical orbit?
Varies with position, minimum at perigee and maximum at apogee.
How does potential energy relate to Lagrangian mechanics?
The Lagrangian L = KE - PE is fundamental in advanced mechanics formulations.
What's the potential energy of a proton in a nucleus?
Described by nuclear potential wells in quantum mechanics models.
How do I calculate potential energy in a crystal lattice?
Sum of all pairwise interactions between ions/atoms in the lattice structure.