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Numbers, Units & Calculators

Ohm's Law Calculator

Calculate a result with Ohm's Law from the values you enter. Enter the required values, adjust the options, and review the calculated result.

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The tool is ready to run.

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Ready for a result

Calculate a result with Ohm's Law from the values you enter. Enter the required values, adjust the options, and review the calculated result.

This tool runs open-source code from OmniTools (MIT License). See open-source credits.

Ohm's Law Calculator solves voltage, current, or resistance from the other two values.

It returns 20 V because voltage equals current × resistance. The calculation runs in your browser. Processing runs in the browser.

Instructions

  1. Provide values for this tool.
  2. Choose the missing electrical variable.
  3. Enter the other two values.
  4. Check units and the denominator before running.

Example

Input: current = 2 A; resistance = 10 Ω

Settings: Ohm's Law Calculator: Unknown: voltage.

Result: It returns 20 V because voltage equals current × resistance.

Limits

  • Ohm's Law Calculator: A zero denominator has no finite result.
  • Ohm's Law Calculator: It models the supplied values, not a complete circuit.
  • Ohm's Law Calculator: It does not verify component ratings.

Questions

How do I calculate voltage with Ohm’s law?

Choose voltage as the output and enter current and resistance. The tool calculates voltage as current multiplied by resistance.

Can the calculator solve for current or resistance?

Yes. Choose the missing variable and supply the other two values. It uses current = voltage ÷ resistance or resistance = voltage ÷ current.

Why does Ohm’s law calculation fail with a zero denominator?

A division by zero does not produce a finite result in this calculator. Check the chosen unknown and ensure the supplied denominator represents your intended circuit model.