LED Resistor Calculator
How to choose an LED resistor
- Enter the supply voltage.
- Enter the LED forward voltage and current from its datasheet, and how many LEDs are in series.
- Use the nearest standard value, and a resistor rated for at least the suggested power.
Frequently asked questions
What forward voltage should I use?
From the datasheet. Typical values are about 2 V for red, yellow and green LEDs and about 3 V for blue and white ones.
Why round up?
A slightly larger resistor gives slightly less current, which keeps the LED within its rating.
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