Ohm's Law Calculator
Calculate voltage, current, resistance and power using Ohm's law. Enter any two known values and the calculator solves for the remaining two using V = IR and P = VI.
Calculate Voltage (V), Current (I), Resistance (R), or Power (P). Fill any two values.
How It Works & Formula
Ohm's law states V = I x R, and power is P = V x I. From any two known values, the other two are derived using these relationships.
Frequently Asked Questions
What is Ohm's law?
Ohm's law states that the current through a conductor is directly proportional to the voltage and inversely proportional to the resistance.
How is power calculated?
Power (watts) equals voltage multiplied by current (P = VI).
Can I solve with just two inputs?
Yes, enter any two of voltage, current, resistance or power, and the calculator finds the other two.