Electric Potential Calculator

About the Electric Potential Calculator

The electric potential calculator determines the voltage, electric field, and potential energy created by point charges at a given distance. Electric potential (voltage) is a scalar quantity that represents the work per unit charge needed to move a test charge from infinity to a point in the electric field, making it fundamental to understanding electrostatic interactions.

Using Coulomb's law and the superposition principle, this calculator handles single charges and two-charge configurations, computing the net potential at any field point. The superposition principle states that the total potential from multiple charges is simply the algebraic sum of individual potentials — unlike vector electric fields, potentials add as scalars, simplifying calculations considerably.

The tool also computes potential energy of a test charge at the field point, the electric field magnitude, and provides a distance table showing how potential falls off as 1/r. It supports dielectric media by incorporating the relative permittivity, which reduces the effective Coulomb constant in materials like water (εr ≈ 80) or glass (εr ≈ 5–10).

When This Page Helps

Electric potential calculations are essential in electrostatics education, capacitor design, semiconductor physics, and electrochemistry. It gives answers for homework problems, lab work, and engineering applications involving charge distributions, with support for dielectrics and multi-charge superposition.

How to Use the Inputs

1. Select single or two-charge configuration
2. Enter the charge magnitude in Coulombs (use scientific notation, e.g. 1e-6 for 1 μC)
3. Enter the distance from the charge to the field point in meters
4. For two charges, enter both charges and their distances to the field point
5. Optionally set a dielectric constant for non-vacuum media
6. Enter a test charge to compute potential energy and force
7. Review potential, field, energy, and the distance reference table

Example Calculation

Tips & Best Practices

• Use scientific notation for charge values (e.g., 1e-6 for 1 μC, 1.6e-19 for one electron)
• Remember that potential is a scalar — no direction needed, just add or subtract values
• In water (εr ≈ 80), electric interactions are reduced by a factor of 80 compared to vacuum
• The electron-volt (eV) equals 1.602 × 10⁻¹⁹ J — useful for atomic-scale energies
• Equipotential surfaces are perpendicular to electric field lines at every point

When To Use This Calculator

Calculate electric potential, field strength, and potential energy for point charges with superposition, dielectric effects, and distance analysis. Use it when you need a repeatable calculation in the physics / general category and want the setup, result, and supporting values kept together. This is especially helpful when small input changes, unit choices, or rounding decisions can change the final number.

How To Check The Result

Start by confirming that the inputs match the formula shown on the page. Then compare the main output with the worked example and any secondary values shown by the calculator. If the result will be used in another calculation, keep extra precision until the final step and record the assumptions beside the number.

Practical Notes

Treat the result as a calculation aid rather than a substitute for context. For schoolwork, include the formula and substitution steps. For planning, technical, financial, or health-related decisions, verify important numbers against primary records, current rules, or a qualified professional before acting on them.

Frequently Asked Questions

• What is electric potential?

  Electric potential (voltage) at a point is the work done per unit charge to bring a positive test charge from infinity to that point. It is measured in volts (V = J/C).

• How does potential differ from electric field?

  Potential is a scalar (magnitude only) and falls off as 1/r. Electric field is a vector (magnitude and direction) and falls off as 1/r². The field is the negative gradient of the potential.

• Why use superposition?

  Superposition allows calculating the potential from multiple charges by simply adding individual potentials. This is much simpler than adding electric field vectors.

• What is the dielectric constant?

  The dielectric constant (relative permittivity εr) measures how much a material reduces the electric field. Vacuum has εr = 1, water ≈ 80, which is why ionic interactions are much weaker in water.

• What are typical charge values in physics?

  Elementary charge: 1.6 × 10⁻¹⁹ C. Microcoulombs (10⁻⁶ C) are typical in electrostatic experiments. Lightning transfers about 5 C. Van de Graaff generators store ~10⁻⁵ C.

• Can potential be negative?

  Yes. Negative charges create negative potentials. The sign indicates whether a positive test charge would gain or lose energy approaching the source charge.