Volts / Amps / Watts Calculator

This calculator uses Ohm's Law (V = I × R, rearranged as P = V × I) to work out volts, amps or watts for a circuit. Enter any two values below and the third is calculated automatically — useful for quick load checks, sizing circuits, or verifying appliance ratings on-site.

Need to quote the job too? Try TradePilot free — describe the work and get a full quote with a professional PDF in seconds.