Welcome to the LED calculator.
You will need to know
- the working voltage of your LED
- the maximum working current of your LED
- The voltage of your supply
Usually when you buy your LEDs the listing will have the working voltage and the working current of your LED Check it!
The working current of your LED is the maximum permissible, it will work with a lower current but its brightness will be lower. Typically domed LEDs will be standard (10ma) suprebright (20ma) or ultrabright (30ma) many smd leds are 20ma but this can vary a lot. Its always best to check the specifications.
If your battery is a rechargeable its voltage rating is the mean voltage value. For example a 7.4 volt 2s lipo fully charged is 8.4 volts, fully discharged it is 6 volts.
LED resistor value calculation |