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Ohm's Law Calculator

Enter any two values to calculate the missing electrical values.

For quick calculations only. Check measured values and safety requirements before using results on real work.

Notes and next steps

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How it works

Calculate voltage, current, resistance or power from two known values.

Formula used: V = I × R and P = V × I.

Worked example

230 V at 10 A gives 2300 W and 23 Ω equivalent resistance.

Common mistakes
  • Entering values with the wrong units.
  • Using it as a design approval tool.
  • Forgetting AC, power factor or real-world conditions.
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