LED Resistor Calculator LED Resistor Calculator LED Resistor Calculator Supply Voltage (V) LED Forward Voltage (V) LED Current (mA) Calculate Resistor This calculator helps you determine the correct resistor value to use with an LED to ensure it operates safely within its specified current range. Enter the supply voltage, LED forward voltage, and desired LED current to find the resistor value. Example Calculation If the supply voltage is 12V, the LED forward voltage is 2V, and the desired current is 20mA: Resistor Value = (Supply Voltage - LED Forward Voltage) / LED Current So, Resistor Value = (12V - 2V) / 0.02A = 10V / 0.02A = 500 Ohms Subscribe to Updates Get the latest creative news from SmartMag about art & design. By signing up, you agree to the our terms and our Privacy Policy agreement.