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LED Series Resistance Calculator

Calculate the resistor, LED current, supply voltage or forward voltage for a simple series LED circuit.

  • Type: Electronics calculator
  • Formula: R = (Vin − Vf) / I
  • Units: Engineering notation
  • Runs locally in your browser

LED series resistor

Select the value to calculate, then enter the remaining values.

Enter values and select Calculate.

Using the result

The calculator uses the ideal textbook relationship shown above. Real components have tolerance and practical circuits can introduce loading, leakage, bandwidth and other effects, so choose real component values with suitable margin for your design.

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