How to calculate power for LED strip lights?

Many people do not know how to calculate the power based on the led strip, so there is no purpose when browsing the led power supply and don’t know how to choose among the various power supply products.

An important principle for choosing an led driver is whether the power is suitable for your LED strip lighting and led light controller. Actually, calculating the power that your LED light strip need is not a difficult thing.

There is a power calculation formula.

Total wattage = Wattage/meter x Length

When calculating the power of your led strip light, you need to follow the 80% principle. The power wattage you choose is 1.2 times more than the calculated theoretical wattage. This way your led light power supply will not overheat and affect its service life.

4 steps to calculate the power your led strip need

Take our 24V waterproof RGB color changing led neon lights as an example.

Step 1. Know the wattage per meter of your led strip light.

The LED light strip product details page will detail the various information required for the LED product. Here you can see the specific number of watts per meter of your led strip.

After entering the product page, slide down the page to find the product specifications, which indicate the working power, and find the power per meter.

And we can know that this 24V RGB color changing neon led lights consume 8 watts per meter.

Step 2. Decide how long you want the length of your led light strip.

Led strip lights are generally 5 meters/16.4ft in a roll, but there are also cases of one meter/3.28ft or two meters/6.56ft in length. Even high-voltage led strip lights can reach 100 meters.

Decide the length of your led strip lighting reasonably according to your project. It can be unpleasant to find that there is a shortage of led light strips when installing your led lighting.

Our 24V RGB neon lights have options of 5 meters, 10 meters, 15 meters, and 20 meters. If you do not find the right length for your LED light project, you can contact us and we provide customized services.

Step 3. Calculate the theoretical power according to the power formula.

Multiply the wattage per meter by the length of the led strip light to get the total theoretical wattage of the led strip. We got an RGB neon led strip that needs 40W to run 5 meters.

Theoretical power : 8w/m x 5m = 40W

Step 4. The 80% rule.

The actual required power is equal to the theoretical power multiplied by 1.2. That is, the power used by the led strip light occupies 80% of the led power supply. This is to leave room for the led transformer to ensure its service life and reduce the possibility of subsequent maintenance.

Actual required power : 40W x 1.2 = 48W

Through calculation, we find that the 5m 24V RGB led neon light actually at least needs a 48-watt led driver power supply to safely power the led light strip. And the longer the length, the more wattage required. Check the below table to get the detailed data.

Not only our 24V RGB led neon rope lights, but this calculation formula also applies to any led strips. As long as you want to calculate the power of the led strip light power supply, you can use this formula.

Watt/meterLengthTheoretical wattageActually required wattage

Choose the right LED power supply for your led strip light

Now, let’s start to choose a suitable led power supply for our 5m 24V led neon lights.

Find the led power supply drivers in the categories. Click into the product category you are interested in, and find the power supply that matches the voltage and power. 

When choosing an LED light driver, it is required to know the characteristics of your light strip. For example, this led neon light is 24V, so we should choose a 24V led driver. If you have waterproof requirements for the led power supply, you should choose among the 24V waterproof led power supply products. 

  • 24V led power supply

Among all 24V led power supplies, there are 24V power adapters, 24V UL-Listed power supplies, and 24V waterproof power supplies. What is the difference?

►The 24V power adapter carrying power is relatively small.

►The 24V UL-Listed power supply has passed the UL certification, the quality is guaranteed, and has a five-year warranty. It provides IP20 non-waterproof and IP67 waterproof power supplies and Class II power adapters for you to choose from.

►The 24V waterproof power supply has more waterproof function than the ordinary power supply, and it is more secure for outdoor use.

• 24V power adapter: 12 / 24 / 48 / 72 / 96 / 120 W
• 24V UL-Listed IP20 power supply: 35 / 50 / 75 / 100 / 150 / 200 / 240 / 320 / 350 / 400 / 450 / 500 / 600 / 750 / 1000 W
• 24V UL-Listed IP67 power supply: 18 / 20.2 / 36 / 50 / 60 / 74.4 / 95 / 100.8 / 150 / 151.2 / 199.2 / 480 / 600 W
• 24V UL-Listed Class II power adapter: 6 / 15 / 18 / 25 / 36 / 40 / 60 / 90 / 120 / 160 / 221 / 280.08 W
• 24V waterproof power supply: 20 / 30 / 40 / 50 / 60 / 80 / 100 / 120 / 150 / 200 / 250 / 300 / 350 / 400 / 500 / 600 W
  • LED power supply option

Therefore, a 5m 24V RGB led neon light with 48W should choose the 48W 24V power adapter, the 50W 24V UL-Listed IP20 power supply, the 50W 24V UL-Listed IP67 power supply, the 60W 24V UL-Listed Class II power adapter, or the 50W 24V waterproof power supply.

One thing to note is that when the power option does not have the same number as the actual required power you calculated, you need to choose a power that is a little larger than your number. 

For example, in the 24V UL-Listed IP20 power supply, there is no 48W power supply, it doesn’t matter to choose the 50W power supply.

If you need to install an led controller, the power required by the LED light controller is the same as the power required by the LED power supply, so the led neon light needs a 48W LED controller.


It is not difficult to calculate the power and choose the right power supply. Be patient and know more about it. You can do the job. If you have other questions, please feel free to contact us. 

Related knowledge: 

How to choose led strip light power supply?

How to choose led strip light controllers?

What are LED neon lights? 

How to make LED neon lights?