Electric Field Calculator
Compute the electric field from a point charge using Coulomb's law
Inputs
Coulomb's law: E = k · |q| / r². Use SI units for the most accurate result. Distances must be in meters.
Default: 8.987551787 × 10⁹
Result:
Tips
- Distance is measured from the charge center to the evaluation point.
- The direction arrow indicates whether the field radiates outward (positive charge) or inward (negative charge).
- Use meters and coulombs when possible to avoid rounding issues.
How electric field strength is calculated
Formula
E = F / q or E = k|Q| / r²
Electric field is force per unit positive test charge. A point charge’s field decreases with the square of distance.
Worked example
A 0.002 C test charge experiencing 6 N is in a field of 3,000 N/C.
Common mistake
Use meters for distance and distinguish the source charge Q from the test charge q.