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Ohm's Law Calculator

Enter any two values — the remaining voltage, current, resistance and power update instantly.

Formula

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

Example

230 V across a 115 Ω heater: I = 2 A, P = 460 W.

FAQ

What does the calculator do with three inputs?

It takes any two and computes the rest — editing a third value recalculates the pair you did not type.

Does Ohm's law always apply?

Only for ohmic (linear) components. Diodes, transistors and filaments (resistance changes with temperature) deviate from it.