basic

Power Dissipation in a Resistor from Voltage and Current Calculator

P = V·I = I²R = V²/R — three forms of power law.

Calculates power dissipated as heat in a resistor: P = V × I. Automatically derives the third quantity (V, I, or R) when any two of the three are supplied.

Daniel Oh By Daniel Oh
Published Last reviewed 1 min read

Inputs

V
A
Ω

Results

Enter values and click Calculate to see results.
Was this helpful?

How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

P = V·I = I²·R = V²/R

In depth

Calculates power dissipated as heat in a resistor: P = V × I. Automatically derives the third quantity (V, I, or R) when any two of the three are supplied.