This calculator finds the electrostatic force between two point charges using Coulomb's law. Enter the two charges and their separation; Coulomb's constant is filled in automatically.
What the symbols mean
- F — electric force (newtons); positive means repulsion, negative attraction.
- k — Coulomb's constant, 8.99×10⁹ N·m²·C⁻² (auto-filled).
- q₁, q₂ — the two charges (coulombs).
- r — distance between the charges (metres).
Worked example
Two 1-microcoulomb charges one metre apart repel with a force of about 9×10⁻³ N.
Want the full story behind this formula? Read our guide: Coulomb's Law.