Blog: Expanded Universe

How much power does a laptop use?

Laptop companies report the capacity of their laptop batteries, and also like advertising that their laptops have however many hours of battery life. It's easy to derive their (advertised) power usage by combining these two numbers. As examples to study, I picked three laptops that Wirecutter recommended, as well as what seems like a well-regarded high-end gaming laptop.

Of course, the laptop companies are encouraged to play up their battery performance, so we should assume their power consumption estimates are low and seek confirmation from third parties. I checked a few review sites and Tom's Hardware seems to have the most aggressive battery benchmarks, as well as the most precision, so:

When they exist, reviews from NotebookCheck measure power consumption even more directly, including a more intense benchmark using Cyberpunk 2077. I decided to just report two of their many measurements here:

For an even more neutral third party, we can turn to EnergyStar, which is run by the U.S. government and reports Short Idle wattage for some computers. I can't find the exact computers I chose above in its database, but for a slightly older MacBook Air EnergyStar reports 3.4 W; for some OmniBook X, EnergyStar reports 3.6 W; for some Lenovo Yoga 7 (not 7i), EnergyStar reports 5.2 W.


I'm not actually here to review laptops or compare their efficiency, just to summarize: during normal everyday usage, a small laptop probably uses 3–6 W, almost certainly between 2 to 12 W; though intense usage, such as a gaming laptop running a graphics-intense game, can use well over 150 W.

The only reason I collected all these numbers is that when I Googled the titular question, the AI overview and a large number of slop websites (including ones allegedly published in 2026) all gave 30 W as a lower bound for typical laptop power consumption. As best I can tell, this is misinformation stemming from confusing the laptop's actual power consumption with its charger's power rating. A modern MacBook Air's charger is indeed 30 W, but that's how quickly the battery charges in the best case, not how quickly the laptop itself consumes power. I tried the query on a few other search engines and LLMs and got ranges that were closer, but still a bit high compared to these more reliable sources I found after some research. So this is my attempt of the day to slightly improve the information environment.