LED Series Resistor Calculator

These calculators work out the values for an LED current limiting resistor.

The first calculator gives values for standard LED types to calculte the resistor value. NOTE: This should only be used if the LED forward voltage and current are not known

The second calculator gives an accurate value using the LED Vf (forward Voltage) an If (forward Current) to calculte the resistor value.

Resistor Value for LED Type

Enter Supply Voltage : V Series Resistor

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Choose LED Type :

Resistor Valueusing Vf and If

Enter Supply Voltage : V Series Resistor

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Enter LED Forward Voltage Vf :V
Enter LED Forward Current If : mA