LED Resistor Calculator

Work out the perfect series resistor to protect LEDs. Enter your supply voltage, LED forward voltage, and desired current to calculate the ideal resistor value.

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Use the fields below, then run the calculation when your assumptions are ready.

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Your result will appear beside these inputs.

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Fill the required fields, then run the calculator to see the result.

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Inputs at a glance
Supply voltage (V)
5
LED forward voltage (V)
2
Desired LED current (mA)
20
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What this tool does

LED Resistor Calculator helps you work out the perfect series resistor to protect LEDs. Enter your supply voltage, LED forward voltage, and desired current to calculate the ideal resistor value.

What you get

LED Resistor Calculator produces a direct output in this page and is designed to keep processing on your device.

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