Coulomb’s Law Calculator

Calculate electrostatic force between two point charges: F = k·|q₁q₂|/r² (in vacuum/air, approx.).

Default ≈ 8.99×10⁹ (vacuum/air).
Can be negative (e.g., -1e-6).
Use scientific notation if needed (1e-6).
Center-to-center distance (r > 0).
Magnitude: F = k·|q₁q₂| / r²
Field from q₁: E = k·q₁ / r²
Force on q₂: F = q₂·E
Assumes point charges and vacuum/air.
Same signs repel, opposite signs attract. Force grows quickly as distance decreases (1/r²).
Real materials can reduce force (dielectric).