Ohm's Law Calculator

Calculate voltage, current, resistance, and power using Ohm's fundamental law of electrical circuits. Enter any two values to calculate the missing parameters.

Input Parameters

Ohm's Law
V = I × R
Voltage (V) = Current (I) × Resistance (R)

Interactive Circuit Diagram

Results & Analysis

Enter values and click Calculate to see results

About Ohm's Law

Ohm's Law is one of the most fundamental laws in electrical engineering, discovered by German physicist Georg Simon Ohm in 1827. It states that the current through a conductor between two points is directly proportional to the voltage across the two points.

Key Formulas:

  • V = I × R (Voltage = Current × Resistance)
  • I = V / R (Current = Voltage / Resistance)
  • R = V / I (Resistance = Voltage / Current)
  • P = V × I (Power = Voltage × Current)

HOW TO USE

Enter any two known values (Voltage, Current, or Resistance) and click Calculate. The calculator will automatically solve for the missing value using Ohm's Law.

FORMULA USED

V = I × R
I = V ÷ R
R = V ÷ I
P = V × I

WORKED EXAMPLE

If a circuit has Voltage = 12V and Resistance = 4Ω, then Current = 12 ÷ 4 = 3 Amperes. Power = 12 × 3 = 36 Watts.

FREQUENTLY ASKED QUESTIONS

Q: What is Ohm's Law?

A: Ohm's Law states that the current through a conductor is directly proportional to the voltage and inversely proportional to the resistance: V = I × R.

Q: Can I use this for AC circuits?

A: Ohm's Law applies directly to DC circuits. For AC circuits, use impedance (Z) instead of resistance (R).

Q: What units does this calculator use?

A: Voltage in Volts (V), Current in Amperes (A), Resistance in Ohms (Ω), and Power in Watts (W).

Q: What if I enter all three values?

A: The calculator uses the first two valid values and verifies consistency with the third.