Ohm’s Law Calculator
Calculate resistance, current and voltage from known parameters
What is unknown
Known parameters
Ω
V
Calculation result
0
Formula used
⚡ What the calculator computes
Ohm’s law calculator finds current, resistance or voltage in a circuit. Ohm’s law states that current is proportional to voltage and inversely proportional to resistance:
I = V / R
where I is in amperes (A), V in volts (V), R in ohms (Ω). Knowing any two values yields the third.
📐 Formulas
I = V / R
R = V / I
V = I × R
💡 Example
V = 4 V, R = 2 Ω → I = 4 / 2 = 2 A.
✅ Tips
- Select the unknown quantity — the other two fields become inputs.
- Use positive values greater than zero.
- For AC circuits with power factor, use the power calculator.