Calculation of Current Limiting Resistor Value for LED Light Emitting Diodes

Single LED circuit
Note: Different manufacturers and different colors have different voltage drops.

Red: 2.0-2.2v Yellow: 1.8-2.0v

White: 3.0-4v Blue: 3.0-4v

Green: 2.0-2.2v 3.0-3.2v The above is for reference only
voltage
  V
LED voltage drop
  V
Required LED current
  mA



Calculating the Current Limiting Resistor
  Ω
The closest standard resistor
 
Calculating Resistor Power
  W
Safe resistance power
  W
Single led with single resistor
LED Series Circuit
voltage
V
LED voltage drop
  V
Required LED current
  mA
Number of connected LEDs
 



Calculating the Current Limiting Resistor
  Ω
The closest standard resistor
 
Calculating Resistor Power
  W
Safe resistance power
  W
LED parallel circuit
voltage
  V
LED voltage drop
  V
Required LED current
  mA
Number of connected LEDs
 



Calculating the Current Limiting Resistor
  Ω
The closest standard resistor
 
Calculating Resistor Power
  W
Safe resistance power
  W

Calculation of Current Limiting Resistor Value for LED Light Emitting Diode