At first, you may feel a bit lost when choosing and buying the power supply you need. As a first step you should calculate the wattage consumption of your LEDs. To do this, you need to know the power per metre of your strip. This figure must first be multiplied by its length and then by 1.20 to avoid possible power overloads. This method calculates the minimum wattage needed for the LED power supply. As an example, this would be the formula for a 3 metre LED strip of 6 watts (W): (3 x 6) x 1.20 = 21.6 W If you cannot find a power supply with that exact wattage, simply choose one that is higher. Remember for your safety and that of your installation, and this is essential, that you should never install lower wattage.