LED Resistor Calculator
Find the series resistor for an LED from supply voltage, forward voltage, and current.
150
Resistor (Ω)
150
Nearest E12 (Ω)
0.06
Resistor power (W)
Size the current-limiting resistor for an LED and get the nearest standard E12 value.
How to use
- Enter the supply voltage of your circuit.
- Enter the LED forward voltage and desired current in mA.
- Read the required resistor and nearest E12 value.
Frequently asked questions
- What is the formula?
- R = (Vsupply − Vforward) / Icurrent, with current in amps.
- Why use the E12 value?
- E12 lists the standard resistor values you can actually buy.