LED Series Resistor

Enter Vs, Vf (per LED), and target I. I’ll calculate the required series resistor R for N LEDs in series, plus power details. Typical Vf by color is listed below.

V
V
Rounds up the resistor to keep current ≤ target.
Typical Vf by LED Color (≈20 mA)
Color Vf (V)
Approximate values. Always verify with your LED’s datasheet at your operating current and temperature.