About this tool
Enter any two of power, voltage, current and resistance, and the rest are solved live using P = V × I and V = I × R. All math happens in your browser.
Frequently asked questions
Which two values should I enter?
Any two of power, voltage, current or resistance. The calculator combines P = V × I with V = I × R to find the others.
What units are expected?
Power in watts (W), voltage in volts (V), current in amperes (A) and resistance in ohms (Ω).