This LED calculator will help you design your LED array and choose the best current limiting resistors values. To get started, input the required fields below and hit the "Design Circuit".

Power supply voltage (V):

• The power source you are using to power up your LEDs (in Volts)

  AAA	1.5V
  AA	1.5V
  C	1.5V
  D	1.5V
  9 Volt	9V
  PC Power Supply	5V (Red) and 12V (Yellow)

• You can also combine two or more batteries in series and get the sum of their voltage
• Make sure you are using a DC (direct current) power source such as batteries, wall transformers and PC power supplies

LED voltage drop (V):

• The amount of power needed, in Volts, for the LED to light properly. This value is usually provided by the manufacturer
• Also known as forward bias voltage or just forward voltage
• If you are not sure of your LED voltage drop use this table for common 3mm or 5mm LEDs:
  

  Infrared	1.6V
  Red	1.8V to 2.1V
  Orange	2.2V
  Yellow	2.4V
  Green	2.6V
  Blue	3.0V to 3.5V
  White	3.0V to 3.5V
  Ultraviolet	3.5V

LED current rating (mA):

• The amount of current needed, in milliamps (mA), for the LED to light properly. This value is usually provided by the manufacturer
• Also known as forward current
• If you are not sure of your LED current rating use 20mA for common LEDs

Number of LEDs:

The number of LEDs in your array

Output:

Wiring Diagram

Schematic

Design Circuit

You need to increase your source voltage

Print

• Power supply voltage (V):
• LED voltage drop (V):
• LED current rating (mA):
• Number of LEDs:

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