These calculators work out the values for an LED current limiting resistor.

The
first calculator gives values for standard LED types to calculte the resistor
value. __NOTE: This should only be used if the LED forward voltage and current
are not known__

The second calculator gives an accurate value using the LED Vf (forward Voltage) an If (forward Current) to calculte the resistor value.

**Resistor
Value for LED Type**

**
Resistor Valueusing Vf and If**