How to find out how much energy a computer uses

Computers and laptops can be a significant expense on your electricity bill compared to other household items, especially if it’s a gaming PC or a workstation for heavy video editing or 3D modeling. However, it is possible to carry out measurements to understand the energy consumption of a particular product in different usage situations.

Consumption estimates

Websites may offer estimates based on computer components (Image: Screenshot/Outervision)

To find out how much power your computer or laptop is using, there are some tools online that can be very helpful. That’s the case with Outervision, which is available for free and should provide an answer within seconds.

To find out the approximate power of your computer, the site asks for the following information: motherboard type, processor, RAM memory, video card, hard disk or SSD storage, and optical drives. Next, the user must highlight how much time they use the computer and how much of that time is spent on heavy tasks.

In addition to displaying the approximate power of the computer in situations of greater stress, the portal will also recommend the minimum power of the power source. In this way, your computer will work without emergency shutdowns or other unpleasant situations.

And how does that translate into an energy bill?

Laptops tend to use less energy (Image: This Is Engineering/Unsplash)

To estimate the real costs of the computer on the account, it is necessary to know how much electricity was consumed by which device. For this, the information obtained in the previous point can be placed in a simple equation:

  • Consumption (in kWh/month) = (PC power x hours of use per day x number of days)/1,000

As a practical example, let’s assume that a particular computer is running at 400 W at its maximum capabilities—that is, during a heavy game or program. This fee is for two hours a day, 30 days a month. In this case the bill would look like this:

  • (400 x 2 x 30)/1,000 = 24 kWh/month

Then just multiply this number by the kWh value, which usually varies a lot depending on location and season. Imagine that the value is, for example, R$1.04 per kWh: in this case, the final cost would be:

It’s worth remembering that this value only applies to computer usage during the time specified in the initial equation. It is possible, for example, to still be on for the rest of the day, but with a lower load — but still causing energy consumption and changes in the final value.

Finding the right consumption

If the estimated value is not accurate enough, it is also possible to use equipment that accurately measures how much energy the computer consumes. Generally, these devices can be found online for values ​​below R$100.

The performance of these products may vary depending on the type and manufacturer selected. However, usually you just plug it into the socket and the computer will be on and then the kWh measurement will be done for the desired time period.

After the consumption is measured, it is possible to multiply the value with the price indicated on the electricity bill and thus determine exactly how much it costs, for example, to use a computer in a month.

How much does each type of personal computer consume?

Gaming PCs are the least economical (Image: Sean Do/Unsplash)

The power consumption of a computer largely depends on what internal components are built into it. More powerful machines will have a much higher consumption than basic models, and laptops are usually the most economical.

More advanced gaming PCs can exceed 1000W in some cases, especially when you factor in things like monitors and other peripherals. Therefore, long playing periods can be very expensive!

Desktop computers are usually between 100 and 200 W, also depending on the peripherals. Finally, regular laptops usually have between 50 and 100 watts, a number that can be tripled in the case of some gaming laptops.

In any case, energy consumption drops significantly in idle mode, when the device is turned on but not in use. Even so, that small expense can make a difference after a few months!

Below is a list of common household appliances, as well as the power of each appliance for comparison:



(on average, values ​​may vary)

Air conditioning 1500 W
A vacuum cleaner 600 W
Electric shower 5500 W
small electric oven 1500 W
a simple refrigerator 250 W
Printer 45 W
Blender 200 W
microwave 2000 W
Electric faucet 2500 W
Cooling fan 100 W

Please Note: the power itself does not determine the price on the electricity bill. For this, it is also necessary to calculate the consumption based on the time of use — a refrigerator can represent a higher consumption than, for example, an electric faucet.

How to save energy on your computer

Tips for saving energy when using a computer are very similar to those recommended for other electronic devices. Often, simply turning off products at strategic times can represent a much lower cost with energy services.

  1. Computers should be turned off when not in use. After all, some energy consumption always occurs, even during moments of rest.
  2. Disconnect external devices. Items like printers and web cameras also use energy all the time, even in small amounts.
  3. Use smart sockets. Accessories of this type can cut the power completely, preventing unwanted consumption — however, be careful with some specific devices, which can be damaged when repeatedly plugged in and out.
  4. Look for the computer’s power settings. Often the operating system itself has power-saving functions, which can be exploited
  5. Only use the laptop while it is charging. Laptops use a bit more power when plugged in with a full battery.

Source: PCMag, TechAdvisory, The Tech Wire, ASAP Guide

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