Resistor Calculator

If you don't have a calculator handy, use this JavaScript resistor calculator to do the math.




Source Voltage =
LED Forward Voltage Drop =
LED Forward Current in Milliamps =
Needed Resistance in Ohms =
Using Closest Standard 5% Resistor
Closest Standard 5% Resistor =
Closest Standard 5% Resistor Wattage =
Actual Current =
Actual Power Dissipated By LED =
Actual Power Dissipated By Resistor =