Ohm’s Law Calculator | Voltage, Current & Power

Easily calculate voltage, current, resistance, and power with our interactive Ohm's Law calculator. Solves for two unknowns. Fast and accurate.

Voltage (V)

Current (I)

Resistance (R)

Power (P)

Formulas Used

Perform a calculation to see the relevant formulas.

Learn More About Ohm's Law

What is Ohm's Law?

Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points. It is expressed with the formula V = I × R, where V is voltage, I is current, and R is resistance.

The Power Formula

Electrical power (P) is the rate at which electrical energy is transferred. It's calculated using the formula P = V × I. By combining this with Ohm's Law, you can derive other variations, such as P = I² × R and P = V² / R.

Practical Applications

Ohm's Law is fundamental in electronics and electrical engineering. It's used to design circuits, determine the correct resistor size, ensure components get the right voltage, and calculate power consumption for safety and efficiency.