basic

Electric Power Calculator

Power, current, voltage, or resistance from any two known values.

Compute electric power from any two of voltage, current, or resistance using P = VI, P = I²R, and P = V²/R.

Daniel Oh By Daniel Oh
Reviewed by Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

V
A

Results

Enter values and click Calculate to see results.
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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. Energy over time: E = P · t.

In depth

Compute electric power from any two of voltage, current, or resistance using P = VI, P = I²R, and P = V²/R.