Ohm's Law Calculator

Enter any two of voltage, current, resistance, or power — get the other two instantly

Ohm's Law & Power Calculator

Core relationships:

V = I × R (Ohm's Law) P = V × I (Power) P = I² × R = V² / R

Fill exactly two fields and the rest are computed.

Voltage (V)

Current (I)

Resistance (R)

Power (P)

Enter any two values to solve the circuit.

Voltage

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Current

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Resistance

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Power

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Tip: The two values you type are used as inputs; the other two are calculated from them.

Given any two of the four quantities, the remaining two follow directly:

Known	Voltage V	Current I	Resistance R	Power P
V & I	—	—	V / I	V × I
V & R	—	V / R	—	V² / R
V & P	—	P / V	V² / P	—
I & R	I × R	—	—	I² × R
I & P	P / I	—	P / I²	—
R & P	√(P × R)	√(P / R)	—	—