Coulombs law charge calculator

Calculate the vacuum electrostatic force between point charges with F = q₁q₂/(4πε₀r²).

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First charge (µC)

Second charge (µC)

More inputs and assumptions

Separation (m)

Answer

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Calculate the vacuum electrostatic force between point charges with F = q₁q₂/(4πε₀r²).

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Precision and calculation record

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Formula and assumptions

Charges are entered in microcoulombs. Positive output means repulsion, negative attraction. Uses the 2022 CODATA vacuum permittivity 8.8541878188 × 10⁻¹² F/m. No material dielectric, charge distribution, radiation or electrical safety model.

Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

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Updated 2026-09-26

Using Coulombs law charge calculator

Calculate the vacuum electrostatic force between point charges with F = q₁q₂/(4πε₀r²).

Next: Force calculator

A worked example

Example inputs: first charge (µc) = 1, second charge (µc) = 1, separation (m) = 1. Signed radial force (N) = 0.00898755178617.

Before you use the result

Example results for first charge (µc)

These examples use Second charge (µC): 1; Separation (m): 1. They are reference calculations, not recommended settings.

First charge (µC)	Signed radial force (N)
0.5	0.00449377589309
1	0.00898755178617
2	0.0179751035723

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