How much does a laptop battery replacement cost?

Roughly a tenth to a quarter of a comparable new laptop, varying with brand and whether the maker or an independent shop does it. Against replacing the whole machine for a short-day symptom, it is nearly always the rational first move: provided the rest of the machine still measures well.

Is it worth replacing the battery on a 5-year-old laptop?

If the machine still holds its performance under load, measure it, and the day-length is the main complaint, yes. If the same machine also throttles hard and struggles with your work, put the battery money toward the replacement instead. The measurement is what stops you paying twice.

Can I keep using a laptop with a dead battery plugged in?

Usually yes, most laptops run happily on mains with a spent (not swollen) battery. You lose surge protection against power cuts, and on some machines a little peak performance that the battery normally supplements. A swollen battery is the exception: replace, do not coexist.

Problems · Battery

When should I replace my laptop battery?

Replace the battery when its full-charge capacity falls below about 60–80% of design and the shorter day bothers you; immediately if it swells; and soon if the machine shuts down with charge still showing.

One sign outranks all others: swelling. A battery pushing the trackpad or case apart is a safety issue: stop using the machine and have the battery replaced now, not at the next convenient weekend.

First, notice when it happens

From the first minute

Shuts off the moment the charger is pulled, or dies at 30–40% showing: the cells can no longer deliver under demand. That battery is functionally done whatever its percentage claims.

Only after minutes of use

The day just keeps getting shorter, months over months: ordinary wear. Track it with the battery report; replace when the number crosses your patience, not when a utility panics you.

The causes, ranked

1. Swelling, the one that will not wait

rare but serious

How to confirm it

A trackpad that clicks strangely or sits proud, a case that no longer closes flat, a bulge underneath. Swollen cells are a physical hazard.

The fix

Power down, stop charging, and get the battery replaced by a shop promptly. Do not press on it, puncture it, or fly with it. This is the only laptop problem on this site with a safety clock on it.

2. Capacity below the thresholds

most common

How to confirm it

The battery report says it plainly: full-charge ÷ design under 80% is felt, under 60% is replacement territory by manufacturers' own standards. Cycle counts in the 300–500 zone (≈1,000 on modern MacBooks) say the same thing from the other side.

The fix

Replace when the number and your life disagree. A desk machine at 65% can serve for years; a travel machine at 75% may already be failing its owner.

3. Sudden shutdowns with charge remaining

common

How to confirm it

Dies at a displayed 20–40%, especially under load or in the cold: aged cells hold voltage until asked, then collapse. The gauge is not lying about charge so much as the cells lying about deliverability.

The fix

Replacement. Until then, treat the last 40% as reserve rather than range.

4. 'Plugged in, not charging' and charging faults

occasional

How to confirm it

Persistent refusal to charge past a point, or the not-charging state with a good charger on a machine without a charge-limit setting turned on. First rule out that a charge limiter (a healthy feature) is simply set to 80%.

The fix

If it is not the limiter: try another known-good charger and port, then suspect the battery or its charging circuit, a shop can tell which in minutes.

5. Unplugged slowness on machines that cap power on weak cells

occasional

How to confirm it

The machine is markedly slower on battery than it used to be unplugged, beyond its normal battery policy. Some firmware limits power draw as cells weaken.

The fix

A battery replacement that restores unplugged speed feels like a performance upgrade, because it is one. Measure the plugged/unplugged gap before and after.

Measure it instead of guessing

Before replacing a battery on a slow machine, separate the two stories: run the test plugged in and unplugged. If the plugged-in curve is also poor, the battery is not your performance problem and the money may belong in cooling instead. If only the unplugged curve sags, the battery case writes itself.

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What software cannot tell you here

We cannot see swelling, cycle count or cell health; the physical checks and the OS battery report own this diagnosis. What we can do is stop you replacing a battery to fix a cooling problem.

Asked, in people’s own words

How much does a laptop battery replacement cost?: Roughly a tenth to a quarter of a comparable new laptop, varying with brand and whether the maker or an independent shop does it. Against replacing the whole machine for a short-day symptom, it is nearly always the rational first move: provided the rest of the machine still measures well.
Is it worth replacing the battery on a 5-year-old laptop?: If the machine still holds its performance under load, measure it, and the day-length is the main complaint, yes. If the same machine also throttles hard and struggles with your work, put the battery money toward the replacement instead. The measurement is what stops you paying twice.
Can I keep using a laptop with a dead battery plugged in?: Usually yes, most laptops run happily on mains with a spent (not swollen) battery. You lose surge protection against power cuts, and on some machines a little peak performance that the battery normally supplements. A swollen battery is the exception: replace, do not coexist.

Name the cause. Three and a half minutes, in the tab you have open.

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