About the Coulomb's Law Calculator

Solves F = kq₁q₂/r² for any missing quantity.

What it is

Enter any three of force, charge q₁, charge q₂, and distance r, and the calculator solves for the fourth using Coulomb's law, classifying the resulting force as attractive or repulsive.

Features

Solve for any variable

Force, either charge, or distance.

Attractive/repulsive

Classified from the signs of both charges.

Unit support

Charge in C, mC, µC, nC; distance in m, cm, mm.

Step-by-step working

Formula shown with full substitution.

Ready to use it?

Free, no sign-up required.

Open the Coulomb's Law Calculator