Your phone battery dies on a published cycle count, not a calendar date. Apple rates the battery in an iPhone 14, and every model before it, for 500 full charge cycles at 80 percent of original capacity [1]. A full charge cycle means using all of the battery’s power, which can take several days of partial charges [3]. iFixit, which sells the replacement kits, reads that same rating as a couple of years of ordinary use, after which the phone asks to be charged far more often and may run slower [4]. That is the quiet reason a two-year-old handset feels finished while its screen and camera still work. The part that resets the counter lists at $47 to $99, so the third year of a phone is a parts decision, not a handset decision [6].
At a glance
- The shift: A phone battery’s service life is published as a full-charge-cycle count, not a warranty period.
- The number: 500 full cycles, Apple’s rating for an iPhone 14 and earlier.
- The risk: Normal wear is excluded from warranty, so the swap is the owner’s bill.
Why the counter beats the calendar
Capacity fades with each of those cycles, and the rating simply says where 80 percent sits. Charge twice a day and the same battery reaches its printed end in half the time it takes on an every-other-day habit, which is why two owners of one model can be years apart.
Apple’s own page splits the generations, and the split is the interesting part. The older rating covers the iPhone 14 and everything before it; from the iPhone 15 the rating doubles at the same capacity threshold [2]. The iFixit guide for the iPhone 15 repeats that doubled number [5]. The page does not say what changed, and I found no source that separates a better cell from a different way of counting. What a buyer sees is two numbers on one page, a whole generation apart.
The European Union has since put a floor under both. Its ecodesign rule sets a minimum cycle count and an 80 percent capacity retention for batteries in phones and slate tablets placed on the market from 20 June 2025 [8]. That floor sits between Apple’s two ratings, which makes the regulation a useful yardstick for reading a spec sheet written by the seller.
The warranty is where the timeline turns. Apple’s one-year cover excludes batteries that wear down from normal use, and its AppleCare plan replaces a battery at no extra charge only once capacity drops below 80 percent [2]. Put beside iFixit’s estimate, the rated end of life lands after the free-repair window has closed.
By the numbers
- 18 to 24 months: iFixit’s estimate of how long Apple’s older rating lasts for most users [4].
- 800 cycles: The European Union’s minimum for phones sold in its market from 20 June 2025 [8].
- 1000 cycles: Apple’s rating for the iPhone 15 generation at the same 80 percent threshold [2].
What the swap actually buys
Priced per rated cycle, the part is cheap. An iPhone 12 kit at $46.99 against its rated cycle count works out to about 9 cents a cycle, while Apple’s $89 service on the same model is about 18 cents [6]. A kit for the iPhone 15 at $49.99 works out to about 5 cents a cycle [7]. That is the whole economics of keeping a handset: the wear item is priced like a consumable, not like a repair.
In months it reads the same way. The kit comes to roughly $2 to $2.60 a month of extra life on the older generation, and Apple’s service to $3.70 to $4.95 [6]. A first-timer can do the job in 30 minutes to a couple of hours with the tools in the box, according to the same page [6]. What I keep noticing is that the cheapest line on the bill decides whether the device is worth keeping at all, and the desk’s own repair-or-replace calculator turns a quote and a replacement price into the ratio that decision rests on.
The catch
The duration iFixit prints beside the rating is a repair vendor’s gloss, not a measurement. The guide states no sample and no method behind it, so it describes the range its own customers report rather than a laboratory result [4]. Apple’s cycle count is the number to hold on to, and the duration is only what that count converts to.
The doubling is unexplained as well. Two ratings sit on one page with no note on what changed between them, and a reader who quotes the newer number as proof that batteries got twice as durable is quoting a spec revision [2]. It may be a better cell. It may be a different test. The published record does not say.
What I keep coming back to is how ordinary the wear is. Nothing fails, nothing is recalled, and the phone simply asks for the charger earlier each month until its owner calls it old. A published cycle count turns that drift into a date you can plan around, which is more than most of the spec sheet offers. It still will not tell you whether the screen survives the next drop, or whether every slow phone is a tired battery, and that is the limit of a number printed by the seller.
Sources
- Apple, “Batteries — Service and Recycling” (iPhone, Watch, iPad and MacBook cycle ratings) — https://www.apple.com/batteries/service-and-recycling/
- Apple Support, “Apple Service and Repair for iPhone” (warranty exclusions and AppleCare battery service) — https://support.apple.com/iphone/repair
- Apple Support, “Determine battery cycle count for Mac laptops” (definition of a charge cycle) — https://support.apple.com/en-us/102888
- iFixit, “iPhone 12 Battery Replacement” (introduction: the 500-cycle rating and the 18-24 month estimate) — https://www.ifixit.com/Guide/iPhone+12+Battery+Replacement/140588
- iFixit, “iPhone 15 Battery Replacement” (introduction: the 1000-cycle rating) — https://www.ifixit.com/Guide/iPhone+15+Battery+Replacement/165733
- iFixit, “iPhone Battery Replacement: Costs and Considerations” (cost table, November 2024 Apple estimates, and repair time) — https://www.ifixit.com/Wiki/iPhone_Battery_Replacement
- iFixit, “iPhone 15 Battery” (product page, Fix Kit price) — https://www.ifixit.com/products/iphone-15-battery
- European Commission, “Smartphones and Tablets” (ecodesign requirements applying from 20 June 2025) — https://energy-efficient-products.ec.europa.eu/product-list/smartphones-and-tablets_en