Ohm’s Law Calculator

Enter any two of voltage, current, resistance and power to solve the remaining values.

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Enter your values

Leave blank if unknown
Leave blank if unknown
Leave blank if unknown
Leave blank if unknown

How to use Ohm’s Law Calculator

  1. Enter Voltage (V), Current (A), Resistance (Ω), Power (W).
  2. Choose the options that match your task and leave genuinely optional fields blank when they do not apply.
  3. Select Calculate / Run and review the result panel.
  4. Check units, assumptions and any limitations shown on the page before using the result for an important decision.

About this tool

Enter any two of voltage, current, resistance and power to solve the remaining values. Use the form above to enter Voltage (V), Current (A), Resistance (Ω), Power (W). The calculation or transformation runs locally in your browser.

Method

The tool combines V = I × R with P = V × I, P = I²R and P = V²/R so any valid pair of known values can determine the other two.

Use appropriate engineering standards, tolerances and safety margins for real hardware or mains-powered systems.

Frequently asked questions

What does Ohm’s Law Calculator do?

Enter any two of voltage, current, resistance and power to solve the remaining values.

What information do I need?

The form is built around these inputs: Voltage (V), Current (A), Resistance (Ω), Power (W).

Does my input get uploaded?

For this tool, the calculation or transformation runs in your browser. Your entered values are not intentionally sent to ToolboxKart for processing.

Is this tool free to use?

Yes. You can use this ToolboxKart tool without creating an account.

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