LED Resistor Finder

An LED resistor is used to limit current through the LED to prevent it from burning out.

The required resistor value is calculated using Ohm’s Law:

 

Resistor (R) = (Supply Voltage - LED Forward Voltage) / LED Current

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• Supply Voltage is the voltage from your power source (e.g. 5V).

• LED Forward Voltage is the voltage drop across the LED (varies by color).

• LED Current is the desired current through the LED (usually 10–20mA).

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LED Type                                      Typical Forward Voltage (V)

Red                                               1.8 – 2.2 V

Green                                            2.0 – 3.5 V

Blue                                              3.0 – 3.5 V

White                                            3.0 – 3.5 V

Yellow / Amber                            2.0 – 2.4 V

Orange                                         2.0 – 2.2 V

Infrared (IR)                                 1.2 – 1.6 V

Ultraviolet (UV)                            3.1 – 4.0 V

RGB LED (each channel)            Depends on color: R ≈ 2V, G/B ≈ 3V

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💡 Note: Always check the datasheet for your specific LED, as values can vary depending on manufacturer and brightness.