Ohm's Law Calculator

Enter any two values to calculate the other two.

V
A
Ω
W
Tip: Enter any two known values and click Calculate to find the other two.

Results

Voltage
-
Volts (V)
Current
-
Amps (A)
Resistance
-
Ohms (Ω)
Power
-
Watts (W)

Ohm's Law Formulas

Find Voltage (V)

V = I × RVoltage = Current × Resistance
V = P / IVoltage = Power / Current
V = √(P × R)Voltage = √(Power × Resistance)

Find Current (I)

I = V / RCurrent = Voltage / Resistance
I = P / VCurrent = Power / Voltage
I = √(P / R)Current = √(Power / Resistance)

Find Resistance (R)

R = V / IResistance = Voltage / Current
R = V² / PResistance = Voltage² / Power
R = P / I²Resistance = Power / Current²

Find Power (P)

P = V × IPower = Voltage × Current
P = V² / RPower = Voltage² / Resistance
P = I² × RPower = Current² × Resistance

The Power Wheel

V P/I I×R √(P×R) I P/V V/R √(P/R) P V×I I²×R V²/R R V/I P/I² V²/P OHM'S LAW

Find any value in the outer ring by using formulas that contain the two adjacent known values.