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LED Parallel/Series Calculator

This calculator uses two equations that are important for designing electronics:

Ohm’s Law

$$V = I \times R$$

and the Power Equation

$$P = I \times V$$

A simple use of these is finding the power rating required for resistors. In this case, enter any two of the following values: the voltage across the resistor, the current through the resistor, or its resistance in ohms to find the power dissipation in watts. This is the minimum power rating you can use on your resistor. Our calculator rounds up to the nearest value to ensure minimum safety.

Circuit Values
Please enter any two of the following three values for your circuit
The number of LEDs you are trying to power
V
The voltage from the power supply.
V
The LED forward voltage drop is usually found in the datasheet for your LED. If you do not have this value, it can usually be determine used a multimeter "diode" setting. This value will likely be between 1.8 and 3.3 volts. A red LED typically has a forward voltage drop of approximately 1.8 volts, increasing to ~3.3 volts in a blue LED as the colors move through the spectrum. If necessary, you can estimate using the following values:
Red or Orange2.0 V
Yellow2.1 V
Yellow2.1 V
Green2.2 V
Blue or White3.3 V
mA
The LED forward current is usually found in the datasheet for your LED.
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