Checking a used MacBook's battery before you buy
Updated 20 August 2026
The seller just told you two numbers — a cycle count and a health percentage. The question in front of you isn't "is this battery dying," it's narrower and more useful: given those two numbers, is the seller telling the truth?
Search for an answer and you'll mostly find guides on where to look, and a scattering of threshold claims — under some number of cycles is "lightly used," over another it's "well into its life." Those thresholds don't cite a source because there isn't one to cite. This page does something different: it puts the pair the seller gave you against 1,539 other real batteries reported at similar mileage, and shows you where it falls.
Where the two numbers live, on a machine that isn't yours
You can read both in under a minute, on the seller's own Mac, with nothing installed. Hold Option and click the Apple menu → System Information → Hardware → Power. Under "Health Information" macOS prints Cycle Count, Condition and Maximum Capacity — three numbers on one screen, read straight from the battery controller, not from an app either of you had to trust.
Is what the seller told you plausible?
Type in the pair they gave you. The answer isn't "good" or "bad" — it's where that pair sits against 1,539 self-reported pairs from other Mac owners at a similar cycle count, narrowed to the same chip if you name one and enough people reported that chip too. If the seller's number lands well below the middle for that mileage, that's a fact worth a follow-up question, not a verdict on its own — a hard-used battery is still a working battery, and the price should already reflect it.
| Cycle count | Median health | Reports |
|---|---|---|
| 0–99 | 98% | 738 |
| 100–199 | 93% | 309 |
| 200–299 | 89% | 179 |
| 300–399 | 87% | 93 |
| 400–599 | 84% | 98 |
| 600–899 | 83% | 50 |
| 900–2,000 | 80% | 72 |
Why we didn't just give you a threshold
Look up "how many cycles is too many" and you'll run into the same handful of claims, worded slightly differently each time: under some number of cycles the battery is "lightly used," a middle range is "normal," and past a third number it's "well into its life." Nobody attaches a source to those splits, because there isn't a dataset behind them — they're repeated from article to article until repetition starts to look like evidence. That's the pattern this page refuses to add to.
What the table above gives you instead is a real distribution: the median battery at 0–99 cycles reports 98% health, and that median works its way down as the cycle count climbs, reaching 80% in the 900–2,000 range — which happens to be where Apple says a pack is designed to sit after 1,000 cycles. That's not us naming a threshold either. It's what 1,539 people typing their own two numbers into Reddit comments actually reported, bucketed by mileage.
What these two numbers don't tell you
Cycle count and health describe the pack, not the used Mac's runtime under your workload — and they don't move together with it. A battery at 96% health can still leave a Mac dead in four hours, because health measures the size of the tank and runtime is capacity divided by how much the machine draws. That's a separate measurement with a separate page: health says 96% but it only lasts four hours. Neither of the two numbers you just checked says anything about watts — how much this particular Mac spends per hour is invisible to both of them, and to System Information generally.
What a seller can hide, and what they can't
Both numbers come from the battery controller's own registry, read live by macOS — not typed in by anyone. That cuts two ways. A screenshot sent over chat proves nothing: it can be an old reading, a different machine, or an edited image, and you have no way to tell from the image alone. The same two numbers, read on the actual Mac while you're standing next to it, are a different thing entirely — there's no step in System Information → Power where a number can be typed in instead of read. If a seller won't let you check in person, that refusal is more informative than any number they send you.
The data behind the table, and where it stops applying
- These are self-reports, not our measurements. The 1,539 pairs come from posts across r/macbookpro, r/macbookair, r/MacOS, r/mac, r/applehelp and r/macbook over three years — someone typing a cycle count and a health percentage into a comment. Nobody weighed a battery or ran it through a lab.
- The data stops at 2,000 cycles. Above that, we have nothing to compare against — a battery with a higher count than that isn't rare in a bad way, it's just outside what anyone reported.
- The sample skews calm, and we measured it. Posts with an alarmed title report a median three points lower than the rest, and the calm posts outnumber the alarmed ones seven to one — so the table isn't a table filled by people mid-panic.
- Below 15 reports, a bucket doesn't answer. Where a chip or a mileage range has too few reports, the calculator says so instead of guessing — that's a rule enforced in the code that builds the table, not a judgment call made per answer.
For the fuller picture — the same 1,539 reports split by chip generation, and the one machine we tracked ourselves at two points three weeks apart — battery health vs cycle count: which one actually matters is the page for it.
Related: health is fine but the Mac only lasts four hours · why your Mac reports two different health numbers · how we count watts, minutes and battery health
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