Ohm's Law Calculator
Calculate Voltage, Current, Resistance, and Power. Enter any two known values to find the remaining two.
Enter any two values to calculate the remaining two.
V
A
Ω
W
Understanding 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.
Formulas
Voltage (V)
V = I × R
V = P / I
V = √(P × R)
V = I × R
V = P / I
V = √(P × R)
Current (I)
I = V / R
I = P / V
I = √(P / R)
I = V / R
I = P / V
I = √(P / R)
Resistance (R)
R = V / I
R = V² / P
R = P / I²
R = V / I
R = V² / P
R = P / I²
Power (P)
P = V × I
P = I² × R
P = V² / R
P = V × I
P = I² × R
P = V² / R
Ohm's Law Triangle
A popular way to remember the formula is the triangle method, where V is at the top, and I and R are at the bottom.
- To find V, cover V: You see I × R
- To find I, cover I: You see V / R
- To find R, cover R: You see V / I