Solve V, I, R or P.. Ohm is a free online tool from the ToolsRift Finance & Health Calculators collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
Enter any two of voltage, current, resistance or power. The calculator applies Ohm's law to solve for the remaining electrical values instantly.
Ohm's law states V = I × R: voltage equals current times resistance. From any two values you can find the third, and power follows as P = V × I.
Power P = V × I, and by substitution P = I² × R or P = V² / R. Enter any two of the four quantities and the calculator derives the rest.
Voltage is in volts (V), current in amperes (A), resistance in ohms (Ω) and power in watts (W). Enter values in these base units for correct results.