A question that often comes up is "what resistor should I use with my LED?" This calculator helps determine that for you.

Fill in the top three fields, then press find R to calculate your resistor value.

Supply voltage V [3-24 V]
Diode forward voltage V [2-4 V]
Diode rated current mA [10-50 mA]
Calculated resistance value Ohms
Next standard 5% resistor * Ohms
Resistor color markings
Power dissipated in LED** mW
Power dissipated in resistor** mW