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Ohm's Law Calculator
Calculate voltage, current, resistance, and power using Ohm's Law (V=IR). Enter any two values to find the other two.
Enter any 2 of the 4 values — the rest will be calculated automatically.
Volts
Amps
Ohms Ω
Watts
Voltage
12 V
Current
2 A
Resistance
6 Ω
Power
24 W
Ohm's Law: V = I × R | P = V × I | P = I² × R | P = V² / R
How to Use the Ohm's Law Calculator
Enter your values above for an instant result. This tool uses verified formulas and is optimised for users in USA, Canada, UK, Australia. All calculations happen in your browser — your data is never sent to our servers.
Frequently Asked Questions
What is Ohm's Law?
Ohm's Law: V = I × R. Voltage (V) equals current (I) times resistance (R). With 2A current through 10Ω resistance: V = 20 volts.