Explainer

What it costs to charge your phone and laptop for a year, in the UK

The laptop is answerable: its battery holds 53.8 watt-hours, so filling it costs about a penny and a half. The phone should be the easier of the two and turns out to be the impossible one — because neither of the companies that make most of Britain's phones publishes a number you can convert into energy.

Written by TechCritic's automated editorial pipeline. No human author is claimed, and no person reviewed this page before it was published. Every figure below was checked by the automated build, which recomputes each cost from the inputs printed beside it and refuses to publish if the sums disagree. Published 8 August 2026. TechCritic is published by Tireless, which sets out how it makes articles in its editorial policy.

The laptop, which can be answered

Apple states that the 13-inch MacBook Air contains a "built-in 53.8‑watt‑hour lithium‑polymer battery".2 That is the useful kind of specification, because a watt-hour is a unit of energy and energy is what electricity is sold by. A kilowatt-hour is a thousand of them, and under the current price cap one costs 26.11p.1

So the sum is short enough to do in your head, which is the point:

cost = (watt-hours ÷ 1000) × unit rate

53.8 ÷ 1000 is 0.0538 kilowatt-hours. Multiply by 26.11p and one full charge of that laptop, from empty, costs 1.40p. Not a penny and a half a day — a penny and a half a charge.

What that costs over a year

The annual figure depends entirely on how often the battery is actually flattened. The three rows below are stated assumptions rather than findings: charging every day, on five days a week, and on three. Each row shows the inputs it was calculated from, so any of them can be checked.

The most demanding of those — a laptop taken from full to empty and back every single day of the year — comes to £5.13. That is the whole answer for a laptop, and it is small enough to be worth stating plainly rather than dressing up.

That comparison is why the question is worth asking at all. Our earlier piece on running costs found that an idle desktop with a large screen costs £98.35 a year to leave switched on. Charging a laptop every day costs £5.13. The device people worry about plugging in every night is not where the money goes; the device nobody thinks about, because it never announces itself, is.

The phone, which cannot

A phone battery is smaller than a laptop battery, so the honest expectation is a figure below £5.13 — probably well under two pounds a year. We are not going to print that number, because we cannot source it.

Apple's technical specifications for the iPhone 17 describe the battery as a "built‑in rechargeable lithium‑ion battery" and then give hours of video playback. There is no capacity figure of any kind — no watt-hours, no milliamp-hours.3 You can learn how long the phone plays video for, and nothing about how much energy it stores.

Google does better and still not well enough. The regulatory guide for the Pixel 10a states a capacity of 5,000mAh and the cell chemistry, and stops there.4 No nominal voltage, and no watt-hour equivalent.

Why milliamp-hours are not energy

This is the part most articles on the subject get wrong, usually by not noticing there is anything to get wrong.

A milliamp-hour measures charge — how much moved. Energy is charge multiplied by the voltage it moved through. The same charge at a higher voltage is more energy, and electricity is billed in energy. So a capacity in mAh is not a partial answer that needs rounding off; it is a different quantity from the one a bill is calculated from, and turning it into energy requires a voltage.

Lithium-ion cells sit in a fairly narrow band of nominal voltage, so a reader who wanted an approximate figure could pick a plausible number and multiply. That is precisely what we will not do. Assuming a voltage and printing the result would produce a figure that looks measured, cites a manufacturer's document, and contains an ingredient the manufacturer never published. Our editorial policy says every figure is traceable to a source a reader can open and check, and a number half-derived from an assumption is not that, however reasonable the assumption.

So the honest state of the phone question is this: the arithmetic is trivial, the price is published, and the input is missing. Not hard to find — missing. Two of the largest consumer electronics companies in the world do not tell you how much energy their phones store.

What this is worth knowing for

Not for saving money. £5.13 a year is not a figure anybody should change their behaviour over, and the point of working it out is to be able to stop thinking about it. If you are looking for somewhere to make a difference to a bill, the earlier piece on running costs is the one with the large numbers in it.

What it is worth knowing for is calibration. A phone charger is the object people most often unplug out of a vague sense of thrift, and it is among the least consequential things in a house. Knowing the size of a number is how you stop guessing at it.

There is a second thing, and it is about the industry rather than the devices. The figure that makes a laptop answerable — a capacity stated in watt-hours — is published because it effectively has to be: air-safety rules for lithium batteries are written in watt-hours, so a laptop maker states one. Nothing obliges a phone maker to publish anything a reader can convert into a cost, and in the two cases we checked, they do not. That is not a fact about batteries. It is a fact about what companies choose to tell you, and it only becomes visible if you try to do the sum.

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