Ohm's Law Calculator

Calculate Voltage, Current, Resistance, and Power

Use this calculator to determine any of the four variables in Ohm's Law: voltage, current, resistance, or power. Enter any two known values to calculate the other two.

How to Use Ohm's Law Calculator

Ohm's Law is a fundamental principle in electrical engineering that describes the relationship between voltage, current, and resistance in an electrical circuit. This calculator helps you apply Ohm's Law to solve for unknown values in a circuit.

Ohm's Law Formulas

The basic formulas of Ohm's Law are:

\[V = I \times R\] \[I = \frac{V}{R}\] \[R = \frac{V}{I}\] \[P = V \times I\]

Where:

  • V is voltage in volts (V)
  • I is current in amperes (A)
  • R is resistance in ohms (Ω)
  • P is power in watts (W)

Calculation Steps

  1. Identify the known values in your circuit (at least two are needed)
  2. Enter these values into the calculator
  3. Click the "Calculate" button
  4. The calculator will determine the missing values using the appropriate Ohm's Law equations

Example Calculation

Let's walk through an example calculation using our Ohm's Law calculator:

Scenario 1: Known Voltage and Current

Given:

  • Voltage (V) = 12 V
  • Current (I) = 2 A

Step 1: Calculate Resistance

\[R = \frac{V}{I} = \frac{12 \text{ V}}{2 \text{ A}} = 6 \text{ Ω}\]

Step 2: Calculate Power

\[P = V \times I = 12 \text{ V} \times 2 \text{ A} = 24 \text{ W}\]

Scenario 2: Known Voltage and Resistance

Given:

  • Voltage (V) = 12 V
  • Resistance (R) = 6 Ω

Step 1: Calculate Current

\[I = \frac{V}{R} = \frac{12 \text{ V}}{6 \text{ Ω}} = 2 \text{ A}\]

Step 2: Calculate Power

\[P = V \times I = 12 \text{ V} \times 2 \text{ A} = 24 \text{ W}\]

Scenario 3: Known Current and Resistance

Given:

  • Current (I) = 2 A
  • Resistance (R) = 6 Ω

Step 1: Calculate Voltage

\[V = I \times R = 2 \text{ A} \times 6 \text{ Ω} = 12 \text{ V}\]

Step 2: Calculate Power

\[P = V \times I = 12 \text{ V} \times 2 \text{ A} = 24 \text{ W}\]

In all scenarios, we arrive at the same set of values:

  • Voltage (V) = 12 V
  • Current (I) = 2 A
  • Resistance (R) = 6 Ω
  • Power (P) = 24 W

This example demonstrates how you can use the Ohm's Law calculator to find unknown values when you have any two known values in an electrical circuit.

Ohm's Law Circuit Diagram

V R I

This diagram illustrates a simple circuit that follows Ohm's Law. The voltage source (V) provides the electrical potential, the resistor (R) controls the flow of current, and the current (I) flows through the circuit. The relationship between these components is governed by Ohm's Law, allowing us to calculate any one value when the other two are known.

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