These days, most of us are reliant on a PC or laptop in some capacity, making them a key part of our everyday lives. 

That's due in part to how capable they are. The thought of one device being able to edit videos, connect with people around the world, play graphic-intensive games and type long documents would have been scarcely believable 20 years ago. 

With so much functionality within a relatively compact form factor, it begs the question: just how much power do these things use?

How to measure PC power use

There are two key methods for finding out how much power your PC or laptop is consuming:

Via software

This is the easiest way to find out an estimate of your device's power consumption, although with only a short analysis period it isn't necessary representative of a full day of usage. 

OuterVision's power supply calculator is completely free to use, and provides information on load wattage, recommended power supply (PSU) wattage and estimated annual costs. 

If you're really well versed in your PC's specs, you can get more accurate information and hardware recommendations via the 'Expert' mode.

Via hardware

If you'd prefer, you can also buy dedicated electricity usage monitors. This is great if you're interested in checking the consumption of various other devices, not just your PC or laptop.

Since it's specifically measuring your device, it's also typically more accurate, with an estimated 0.5% error margin. There are plenty of affordable usage monitors on Amazon, including great options from Sinhery and Lowenergie

They are incredibly easy to use. Just plug the PC or laptop into the monitor and then the whole thing into your power supply. Within a few seconds, it should display the energy consumption of that device, usually in kilowatt-hours (KWh). 

How much power should my PC or laptop use?

If you're having trouble interpreting the result, it's worth comparing it to the average figures to get an idea of how efficient your devices are. 

According to Smarter Business, the average PC in the UK uses around 100W of energy per day, or 0.1KWh. A laptop is about half of that at 50W, or 0.05KWh.

That information is based on an average 8-hour working day, and assumes that video editing and gaming aren't part of your workflow. There are obviously a number of factors that these averages can't take into account, but it can offer a useful point of comparison. 

Why do I need to measure PC power use?

Keeping an eye on the power consumption of your PC or laptop is important for a number of reasons. 

Should you ever need to buy a replacement charger, it's crucial to get the right wattage. This will ensure you get the maximum charging speeds, without causing damage to the hardware. 

The internals of most desktop PCs can also be upgraded, but you'll want to make sure these new parts don't significantly increase power consumption. New processors often require a larger power supply, so it pays to be prepared. 

Also, if you're keeping a close eye on electricity consumption, it might be a good idea to have a rough idea of the consumption of your primary productivity device.