Power Law Solver (P/V/I/R)
Solve for any of power, voltage, current, or resistance given any two of the others. Combines P = V·I, P = I²·R, P = V²/R, and Ohm's law.
Limitations: DC + steady-state assumption. For AC, the V·I product is APPARENT power (VA), not real power — use the AC Power Calculator for power-factor-aware computation.
What to do next: Leave the variable you want to solve for blank. Provide any two of the other three quantities. The "Formula used" output tells you which algebraic branch produced the answer.