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Ohm's law calculator

Enter any two of voltage, current and resistance; get the third plus power.

V
A
Leave one box empty
Ω

Calculating…

How it's calculated

V = I × R I = V ÷ R R = V ÷ I P = V × I = I² × R = V² ÷ R

Ohm's law links voltage, current and resistance in a resistive circuit. Leave the value you want to find empty and fill in the other two.

  • A 24 V coil drawing 0.5 A has a resistance of 48 Ω and dissipates 12 W.
  • For AC motors and other inductive loads, current also depends on impedance and power factor. Use the electrical power calculator instead.