Ohm's Law Calculator
Calculate voltage, current, resistance, and power — enter any 2 values to solve for the rest, with auto unit scaling
Ohm's Law
Enter any 2 values, the other 2 are computed
Results
Voltage
Input
12.0000 V
≈ 12.000 V
Current
0.120000 A
≈ 120.00 mA
Resistance
Input
100.00 Ω
≈ 100.00 Ω
Power
1.4400 W
≈ 1.4400 W
Formulas
V = I × R
Voltage
I = V / R
Current
R = V / I
Resistance
P = V × I
Power
P = I² × R
Power
P = V² / R
Power
Ohm's Law
Ohm's Law states the current through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance: V = I × R. Combined with the power equation P = V × I, knowing any 2 of V, I, R, P lets you derive the other two.
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