LED resistor calculator

Calculator and formulas for calculating the LED series resistor

Calculate the LED series resistor

LEDs are usually operated via a series resistor. The series resistor must be dimensioned in such a way that the supply voltage and the maximum permissible current are not exceeded. You can calculate the size of the resistor on this page.

LED resistor calculator

Source voltage V
LED voltage V
LED current
Decimal places
Series resistor Rv
Resistor Power Pv
LED Schaltung


\(\displaystyle V_S \) Source voltage

 \(\displaystyle V_D \)  LED voltage

\(\displaystyle I_D \) Maximum LED current

\(\displaystyle R_V \) Serial resistance

\(\displaystyle P_V \) Serial resistance power rating

Formulas for LED series resistor

Serial resistance \(\displaystyle R_v=\frac{V_S - V_D}{I_D}\)
Serial resistance power rating \(\displaystyle P_v=(V_S - V_D) · I_D\)     \(\displaystyle =I_D^2 · R_v\)

Is this page helpful?            
Thank you for your feedback!

Sorry about that

How can we improve it?