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· Last updated：2026-09-01
V = k·Q/r with the sign preserved, plus the electron potential energy U = −e·V in eV — at the Bohr radius this reproduces 27.2114 V, twice hydrogen's ionization energy.
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Tool usage guide
The Electric Potential Calculator computes the electrostatic potential (V = k·Q/r) around a point charge and determines the resulting potential energy (U = −e·V) for an electron in electronvolts (eV).
Background
A student is solving an introductory electromagnetism assignment on static point charges in vacuum.
Problem
Determine the voltage and electron binding energy 1 metre away from a 1 µC charge.
How to use
Set Charge Q to 1 with unit 'uC', and Distance r to 1 with unit 'm'.
Outcome
Calculates an electric potential of 8987.55 V and an electron potential energy of -8987.55 eV.
Background
An instructor needs to demonstrate the connection between the proton's electric potential and hydrogen's ionization energy.
Problem
Find the electric potential created by a proton (1.60218e-19 C) at the Bohr radius (5.29177e-11 m).
How to use
Set Charge Q to 1.602176634e-19 C and Distance r to 5.29177210903e-11 m.
Outcome
Yields an electric potential of 27.2114 V and U = -27.2114 eV, illustrating twice the 13.6 eV ionization energy.
It uses V = k·Q/r, where k is Coulomb's constant (8.98755 × 10⁹ N·m²/C²), Q is the source charge, and r is the distance.
The electron potential energy is calculated as U = −e·V, directly yielding electronvolts (eV) from the potential in volts.
Yes, entering a negative charge value preserves the sign, resulting in a negative potential and a positive electron potential energy.
You can select Coulombs (C), millicoulombs (mC), microcoulombs (µC), nanocoulombs (nC), or picocoulombs (pC).
Supported units include metres (m), centimetres (cm), millimetres (mm), micrometres (µm), and nanometres (nm).