Frequently Asked Questions
Everything you need to know about the Coulomb's Law Calculator.
How does the Coulomb's law calculator work?
Enter two charges and the distance between them, and it applies F = kq1q2/r² to compute the electrostatic force.
Is it free?
Completely free, no sign-up, downloads, or limits.
What is Coulomb's constant?
k ≈ 8.988×10⁹ N·m²/C², a fixed constant in Coulomb's law relating charge, distance, and force.
How do I know if the force is attractive or repulsive?
The calculator checks the signs of both charges: opposite signs mean attraction, same signs mean repulsion, and it states this explicitly.
Does it handle tiny charge values?
Yes, charges can be entered in microcoulombs, nanocoulombs, or scientific notation.
Does it show the steps?
Yes, the formula — including the value of k — and substitution with your actual values are shown.
What if I enter zero distance?
This is flagged as invalid since it produces an undefined (infinite) force.
Can it solve for charge or distance instead of force?
Yes, choose which quantity to solve for and enter the other three.
Is my data stored?
No; everything runs in your browser and isn't stored or sent anywhere.
Does it work on mobile?
Yes, fully responsive on all screen sizes.