LED current limiting resistor calculator

Calculates a current limiting resistor for LEDs.

Example 1: Must calculate the resistor for a led string of 4 green 5mm leds and 12V supplyView example
Supply voltagevolts
Target currentamperes
Led color 
Leds in seriespcs
E-series 
Results
Total voltage drop in leds3.6 volts
Required resistor70 ohms
Nearest resistor in E-series82 ohms
Resistor power loss~23.902439 milliwatts
Current with selected resistor~17.073171 milliamperes