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Ohm's Law Calculator

Solve for voltage, current, or resistance using Ohm's Law — V = I × R.

4.2M usesUpdated · 2026-04-23Runs locally · zero upload

How to use

  1. Choose which quantity to solve for using the tabs: Voltage (V), Current (I), or Resistance (R).
  2. Enter the two known values.
  3. The result updates instantly.

Formula

The three forms of Ohm's Law:

$$V = I \times R \quad I = \frac{V}{R} \quad R = \frac{V}{I}$$

Where V = voltage (volts), I = current (amperes), R = resistance (ohms).

Example

A 12 V battery connected to a 6 Ω resistor:

$$I = \frac{12}{6} = 2 \text{ A}$$

Frequently asked questions about Ohm's Law Calculator

What is Ohm's Law?

Ohm's Law states that the voltage across a conductor is directly proportional to the current flowing through it, with resistance as the proportionality constant — V = I × R.

What units are used?

Voltage in volts (V), current in amperes (A), and resistance in ohms (Ω).

Does Ohm's Law apply to all components?

Ohm's Law applies to ohmic (linear) resistors. It does not hold for non-linear components like diodes or transistors in most operating regions.