LED Series Resistor Calculator

Calculate the current-limiting resistor for one or more LEDs in series, its power rating and the nearest standard value.

How to use the LED Series Resistor Calculator

Enter or select: Supply voltage, LED forward voltage, LED current, LEDs in series.
Fill in what you know of: Custom forward voltage — leave the unknown empty.
The results (Exact resistance, Nearest E12 (≥), Resistor power, Recommended rating, Actual current with E12) are calculated instantly as you type.
Use “Copy link” to share the calculation with the same input values.