How Much Power Does a Computer Use in Sleep Mode?

Almost everyone uses a computer, be it for private or business purposes. Computers know to consume a lot of power, especially when they are used for some tasks such as playing video games or using photoshop. Therefore, it is recommended that when we don’t use them, to reduce power consumption to a minimum. That’s why we have a sleep mode. But how much power does the computer consume in sleep mode? After I did some tests, I was surprised by the results.

How Much Power Does a Computer Use in Sleep Mode?

So How Much Power Does a Computer Use in Sleep Mode? Most computers typically consume between 3 to 10 watts in sleep mode. To run a computer in sleep mode for a day (24h), it will cost you 0.06 cents by the current price of 13 cents per kWh. During normal mode, the desktop computer uses 60 to 300 watts of power which is around 30 times more than in sleep mode.

Unlike computers, laptops during sleep mode consume around 2 watts of power. In sleep mode, the power of the computer is suspended to all devices, except for the RAM memory. When you press the power button on your PC, it triggers the software to resume with all the process which had previously been initiated and to “awake”.

Power Consumption of Sleep Mode:

  • Computer In Sleep Mode: 3 to 10 watts
  • Laptop In Sleep Mode: 2 watts
  • Tablet In Sleep Mode: 1 watts

If you are one of those who are looking for a new computer, here is our Recommendation.

How Sleep Mode Works?

In sleep mode, our computer will keep the RAM memory together with all of our USB devices powered. The USB devices can go either into sleep mode or continue to run. If you for example have a USB mouse, the lights on the mouse will be turned off when the computer is in sleep mode, and when you press a button on a mouse it will wake up the PC. But to find out how sleep mode actually helps us to save energy, I did a test.

In the test, I used my computer in sleep mode and measured the power consumption that was 0.045 A at 251 VAC (that is around 12 Watts). This can be compared like you fully charged your phone two times. If we take the average price of 13 cents per kWh in the US, that’s around 14 dollars per year if the PC was in sleep mode for the whole year.

However! Putting my computer into hibernate mode dropped the energy usage by 1 watt – less than 1% compared to when it was idle in a sleep state. The difference between laptop is that it will use 1 Watt in sleep mode, while the desktop computer will use 5 to 10 Watts in sleep mode as we mentioned above.

Computer Power Consumption: Sleep Mode Vs Regular Mode

Computer during the regular mode uses on average between 60 to 300 watts per hour, while the computer in sleep mode consumes between 3 to 10 watts. As you can see, this is a pretty big range, and that’s why it is recommended to use sleep mode whenever possible. This is a difference of almost 30 times less.

The computer in normal mode uses the power to run itself (170 W), the internet modem (5 to 10 W), the speakers (20 W), and sometimes the printer (5 W). Therefore, if you run a computer for 8 hours per day, the annual power consumption will come to around 550 kWh. Here is another test I did.

Example Of Test:

The test I did was done by measuring the current that my computer was used by the device a Kill a Watt Meter.

  • When my PC was Off: 0.015A, 3.5 W
  • When my PC was in sleep mode: 0.017A, 3,9 W
  • No Apps running: 0.2 A, 75 W
Regular Use60 to 300 watts30 to 70 watts15 to 30 watts
Sleep Mode3 to 10 watts2 watts1 watts
Power Consumption Table of Computer

If you want to know How Much Power Does a Wi-Fi Router Consumes, read this article.

Is it Better to Put Computer on Sleep or Shutdown?

If you need to use your computer as fast as possible and continue to work where you stopped, then you will put it in sleep mode. If you’re done with using your PC for that period of time or day, then you shut down your computer.

Other factors that are also important are how many applications are running on your computer. If your PC doesn’t have many apps opened, you can put it in sleep mode, where the display, disk, and other major power consumers will not consume energy.

How to Actually Measure Power Consumption?

If you really want to know how much power your computer uses in sleep mode, then you must get a Kill A Watt Meter. Sometimes it is very difficult to accurately measure the electrical consumption of devices that consume very little energy.

By using this device, you will get the exact number of watts that your PC uses. This is a very handy tool, that you can also be used to measure any other electric device in your home. You can get it here on Amazon.

Is it OK to Leave Your PC on Sleep Mode?

When you are taking short breaks from your PC, then the sleep mode is best suited. Sleep mode main purpose is to save energy just for situations like this. Therefore, you don’t have to worry about energy consumption. The great thing about sleep mode is that you can adjust it as you wish (set the time to activate).


Sleep mode is a feature that helps us save energy when we are not at our computer. Although sleep mode can be useful, there is a big difference between normal computer operation and sleep mode in terms of some big savings. Sleep mode allows us to quickly get back to the tasks we had started before and it is not necessary to wait for a computer to turn on. I hope this article has helped you and if you have additional questions feel free to contact us.


I'm the CEO and founder of Home Hacks DIY. I have been involved in home improvement since my early age. I will try to pass you my knowledge and expertise in this industry in which I have been involved for the last 10 years.

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