Electric Potential of a Point Charge Calculator
Find the electric potential a point charge produces at a given distance, plus the potential energy of an optional test charge placed there.
C
m
C
Voltage produced by the point charge at distance r
- 1
Numerator k·q
8.9875×10⁹ × 0 = 8.9875k = 8.9875×10⁹ N·m²/C² is the Coulomb constant. - 2
Electric potential V = k·q ÷ r
8.9875 ÷ 0.1 = 89.8750
How does this calculator work?
The electric potential of a point charge is V = k·q/r, where k = 8.9875×10⁹ N·m²/C². Enter the charge in coulombs and distance in meters to get V in volts; the sign of q is kept. Add an optional test charge q0 and the tool also returns its potential energy U = q0·V in joules.
Formula
How this is calculated
The calculator takes the source charge q in coulombs and the distance r in meters. The electric potential at that point is V = k·q/r, where k = 8.9875×10⁹ N·m²/C² is the Coulomb constant. The sign of q is preserved: a positive charge gives a positive (higher) potential and a negative charge gives a negative potential, all measured relative to zero potential at infinite distance.
If you also supply a test charge q0 in coulombs, the calculator reports the electrostatic potential energy of that charge at the point, U = q0·V joules. This is the work needed to bring q0 from infinity to distance r. For reference it also shows the field magnitude E = k·q/r², which relates to potential by V = E·r for a single point charge.
Assumptions: a single isolated point charge in vacuum (or air, k essentially unchanged), distances in meters and charges in coulombs, with the reference potential set to zero at infinity. The distance r must be nonzero, since the potential diverges as r approaches the charge; the calculator returns no result when r = 0 or any required input is missing or non-numeric.
Frequently asked questions
Electric potential V (in volts) is energy per unit charge created by the source charge and exists whether or not anything is there. Potential energy U = q0·V (in joules) is the energy a specific test charge q0 actually has at that location.
A positive source charge raises the potential (V > 0) and a negative one lowers it (V < 0), relative to zero at infinity. The sign carries through to U, so two like charges give positive (repulsive) energy and opposite charges give negative (attractive) energy.
It uses the Coulomb constant k = 8.9875×10⁹ N·m²/C², equal to 1/(4πε₀) in vacuum. Air changes this by less than 0.1%, so the same value is fine for most everyday problems.
Also known as
TG we-Calculate Editorial Team. (2026). Electric Potential of a Point Charge Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/electric-potential-calculator
TG we-Calculate Editorial Team. "Electric Potential of a Point Charge Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/electric-potential-calculator.
TG we-Calculate Editorial Team, "Electric Potential of a Point Charge Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/electric-potential-calculator
@misc{wecalculate_electric_potential_calculator, title = {Electric Potential of a Point Charge Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/electric-potential-calculator}}, year = {2026}, note = {TG we-Calculate} }
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