Ohm's Law Calculator

Calculate voltage, current, resistance, and power instantly

Calculator

Enter any two values to calculate the other two:

V
A
Ω
W

About Ohm's Law

Ohm's Law is a fundamental principle in electrical engineering and physics that describes the relationship between voltage, current, and resistance in an electrical circuit.

Ohm's Law Triangle Diagram

Ohm's Law Triangle (V = I × R)

The Ohm's Law Formula

V = I × R

Where:

  • V = Voltage (in volts)
  • I = Current (in amperes)
  • R = Resistance (in ohms)

Power Formula

Power (P) in watts can be calculated using:

P = V × I

Or alternatively:

P = I² × R

P = V² / R

How to Use

  1. Enter any two known values (voltage, current, resistance, or power)
  2. Leave the other two fields empty
  3. Click "Calculate" to compute the missing values
  4. Use "Reset" to clear all fields
Tip: You can calculate power by entering any two of voltage, current, or resistance.

Common Questions

Ohm's Law is used to calculate voltage, current, or resistance in electrical circuits. It's essential for designing circuits, troubleshooting electrical problems, and understanding how electrical components interact.

Yes! Our advanced Ohm's Law calculator can calculate power (in watts) when you provide any two of voltage, current, or resistance values.

This calculator provides accurate results for DC circuits and AC circuits with purely resistive loads. For reactive AC circuits (with capacitors or inductors), you'll need to consider impedance (Z) instead of just resistance.

Calculation History

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