Ohm's Law Calculator
Quickly calculate voltage, current, resistance, or power. Enter any two values and Sparky does the rest.
V = voltage (volts), I = current (amps), R = resistance (ohms), P = power (watts)
Enter any two values to calculate the rest.
Common formulas used
V = I × R
I = V ÷ R
R = V ÷ I
P = V × I
This calculator is intended as a quick reference only. Always follow electrical safety practices and local code requirements.
Related problems and reference
Planning and safety note
This content is for general learning and planning. Always verify work against current NEC requirements, manufacturer instructions, and local code rules. If you are unsure or see heat, sparks, burning smell, repeated trips, or damaged wiring, contact a licensed electrician.