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So I recently bought an inverter from amazon to charge my laptop in the car. The inverter was rated 300W, more than enough for my laptop. But it got me curious about how many watts a laptop actually uses. So I researched.
In this blog, I’m sharing what I found.
Power consumption is variable
A laptop’s power consumption depends on a few factors, the most important one being load. A modern laptop uses very little power when idle. When you do resource-intensive tasks, it draws more power. Another factor is screen brightness; a brighter screen consumes more power.
Moreover, different models have different sets of components, so power consumption varies significantly. For example, a gaming laptop usually consumes more power than a Chromebook when idle. Besides, modern hardware (e,g CPU, GPU) is becoming more energy efficient. So chances are that your old laptop uses more power than modern versions.
How many watts does my laptop use?
Typically, modern laptops consume less than 30 watts while idle. Nowadays laptops are designed to be energy efficient, so they use minimal power in idle mode. Under moderate load, laptops can consume 40-60 watts.
This number goes up when doing resource-heavy tasks like gaming or video editing. An average gaming laptop under heavy load can use as much as 90 watts. And newer gaming laptops like the Acer Predator Triton 500 consume even more power, surpassing the 100 watts mark.

How many watts does a laptop charger use?
The power consumption of your charger is completely dependent on the laptop. If your laptop power demand is 40 watts, The Charger will draw a little over 40 watts from the outlet.
If the battery isn’t full and charging, the laptop will draw even more power from the charger. When the laptop is idle and charging, the charger can consume 40-60 watts. Under considerable load on CPU/GPU, the number goes up.