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Coulomb's law F = k·|q₁q₂|/r² with signed charges and unit selectors, reporting the force magnitude and whether the pair attracts or repels.
Execution
Fill in the form, run the tool, and review the result in one place.
Samples
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Tool usage guide
The Coulomb Force Calculator computes the electrostatic interaction force between two point charges using Coulomb's law: F = k·|q₁q₂|/r². By supporting positive or negative values across multiple charge units (C, mC, µC, nC) and distance scales (m, cm, mm, µm, nm), it quickly provides the exact force magnitude in newtons alongside the interaction type (attractive or repulsive).
Background
A teacher is demonstrating why everyday electrostatic charges are measured in microcoulombs rather than full coulombs.
Problem
Calculate the theoretical force between two 1 C charges placed 1 meter apart.
How to use
Set q₁ to 1, q₂ to 1, chargeUnit to 'C', r to 1, and rUnit to 'm'.
Outcome
Calculates a repulsive force of 8.98755 × 10⁹ N, illustrating the massive scale of one coulomb.
Background
A student needs to calculate the electrostatic force binding an electron and proton at the Bohr radius (5.29177 × 10⁻¹¹ m).
Problem
Find the attractive force between charges of -1.60218 × 10⁻¹⁹ C and +1.60218 × 10⁻¹⁹ C at atomic distances.
How to use
Input q₁ as -1.602176634e-19, q₂ as 1.602176634e-19 in 'C', with r set to 5.29177210903e-11 in 'm'.
Outcome
Returns an attractive force magnitude of 8.23872 × 10⁻⁸ N holding the electron in orbit.
The calculator uses standard vacuum permittivity to apply Coulomb's constant k ≈ 8.98755 × 10⁹ N·m²/C².
Charges with identical signs (both positive or both negative) repel, while charges with opposite signs attract.
Yes, you can enter signed numbers to indicate polarity, which determines whether the resulting force attracts or repels.
Charges can be set in C, mC, µC, or nC, and distances can be set in m, cm, mm, µm, or nm.
The calculator computes forces in a vacuum (or air) using the standard electrostatic constant k without additional dielectric medium scaling.