Electronics 2000

LED Series Resistor Calculator

These calculators give values for LED current limiting series resistors. The first calculator gives values based on standard LED types. This should only be used if the LED forward voltage and current are not known. The second calculator gives a more accurate value using these figures, which can be found in the suppliers catalogue.

Calculate Resistor Value for Common LED Types:

Enter Supply Voltage:
       Volts
Arrow Arrow Resistor =

Ohms

Choose LED Type:
      

Calculate Resistor Value from Vf and If:

Enter Supply Voltage:
       Volts
Arrow Arrow Resistor =

Ohms

Enter LED Forward Voltage, Vf:
       Volts
Enter LED Forward Current, If:
       Milliamps