← Circuit Toolkit

Ohm's Law Calculator

Solve V = IR for voltage, current, resistance, or power

Ohm's Law states V = I × R. Combined with P = V × I, any one of the four quantities can be found from any two others. The calculator solves all four formulas simultaneously.

The four formulas

V = I × R  ·  I = V / R  ·  R = V / I  ·  P = V × I = I² × R = V² / R

Practical notes

Ohm's Law applies to resistive (linear) elements only — not to diodes, transistors, or reactive components. Power dissipated as heat: P = I² × R.