Resistor to diode LED

                   Every LED has a specified maximum current, exceeding this value will damage it. To protect or limit current, we simply use a resistor in series with it.  This LED resistor calculator will help you choose the right resistor value for your LED.


  • Vs is the source voltage, measured in volts (V)
  • Vled is the voltage drop across the LED, measured in volts (V)
  • Iled is the current through the LED, measured in Amperes (Amps/A)
  • R is the resistance, measured in Ohms (Ω).

Enter the data:

Voltage Source: Volts
Current through the LED: Ampers
Voltage drop from LED:

You need a resistor: