What does a laptop cost to run?

A laptop is one of the most efficient computers you can use, designed from the ground up to sip power so it can run on a battery. Even working hard it typically draws only 30-65W, a fraction of a desktop, and once the battery is charged it falls back to barely more than the screen and processor need.

The whole engineering brief of a laptop is to make a charge last, and that discipline shows up on your power bill. Every part, from the low-voltage processor to the LED screen backlight, is tuned to waste as little as possible. A desktop has no such constraint, so it happily pulls two, three or more times the power to do the same web browsing, email and word processing.

That efficiency is why 'work on the laptop instead of the desktop' is sound advice if you are cost-conscious, because over a full working day the difference is real. If you spend hours a day at a computer for work or study, simply choosing the laptop for that time quietly trims the bill compared with sitting at a power-hungry tower.

There is little to optimise beyond the obvious. It charges to full and then largely stops drawing, so leaving it plugged in is not wasteful in the way people fear. The charger tops the battery up and then idles at a trickle, rather than continuing to pour power in, so you can leave it on the desk without guilt.

The usual small-load habits still apply if you want to be thorough. Dimming the screen and letting the machine sleep when you step away shave a little more off an already tiny number, and unplugging the charger removes its last few watts of standby draw. None of it will move your bill in any noticeable way.

As a power-bill item the laptop is comfortably minor. It is here mostly to show how far ahead of a desktop it sits, and to reassure you that the family laptop is not what is driving your bill up. If you want to see just how small it is next to the appliances that do matter, add it to the calculator alongside the heating and hot water and watch where it lands.