LED Series Resistor Calculator
This tool calculates the resistor needed to drive one or more series LEDs from a voltage source at a specified current.
Note: to keep the resistor from overheating, choose one with a power rating 2–10 times the calculated dissipation.
V
V
mA
=Ω
=W
Formula
R=Vs−VfIf
| LED Color | Typical Vf Range |
|---|---|
| Red | 1.8 to 2.1 |
| Amber | 2 to 2.2 |
| Orange | 1.9 to 2.2 |
| Yellow | 1.9 to 2.2 |
| Green | 2 to 3.1 |
| Blue | 3 to 3.7 |
| White | 3 to 3.4 |