Updated August 2026 · Pixel cutoffs and thresholds quoted from Google's own support pages and app prices from their own Play listings, read on 19 August 2026; where a claim rests on tech-press reporting instead, the section says so
Check Settings, Battery, Battery health first, because a Pixel 8a or newer gives a capacity estimate with nothing to install. On a recent Galaxy, run Samsung Members' battery diagnostic, because it covers nearly every model even where Samsung's newer Battery information screen has not arrived yet. Elsewhere, install AccuBattery and charge normally for a while, because it measures real charge sessions rather than guessing. Dialer codes are real but thinly documented, so treat them as a last resort. Data checked: 19 August 2026.
For years, checking battery health was the one thing iPhone owners could do that Android owners could not, at least not without third-party apps and guesswork. Android 16 changed that: Pixels now have a native Battery health screen reporting an estimated capacity percentage, the way iOS has since 2018, and Samsung has begun adding its own battery information screen, starting with the Galaxy S25 series. The catch is device support, so this guide covers every route, what the numbers mean, and whether a battery needs replacing or just better habits.
One scope note: if a battery empties too fast rather than having physically aged, that is a different problem, covered in the guide on fixing fast battery drain on Android.
The best-documented number, if your Pixel supports it
Settings > Battery > Battery health, then Battery capacity for the number · estimated capacity vs a new battery · Pixel 6a, 7, 7 Pro, 7a, 8 and 8 Pro excluded · checked 19 August 2026
The best-documented option on this page when it is available: a capacity figure Google publishes thresholds for, built into Android 16 with no app to install. Google is explicit that the number is an estimate, not a sensor reading.
Skip it if your phone is not a Pixel 8a or newer, in which case skip straight to Samsung's tools or AccuBattery. Use it over anything else if your Pixel supports it, since nothing else here pairs a figure with a published threshold for acting on it.
A rolling-out screen, plus a fallback that works on more Galaxies
Settings > Battery > Battery information, where present · Samsung Members runs a battery-status diagnostic, per its own listing · exact result wording could not be confirmed today · checked 19 August 2026
Samsung split this across more than one place, and the newest option is still rolling out unevenly by model and region, with fewer details independently confirmable than Google publishes for Pixel.
Skip it if a documented capacity figure with a published threshold matters more than convenience, since that remains more reliably available on a supported Pixel. Use Samsung Members as the fallback on any Galaxy where the newer Battery information screen has not arrived yet.
Real, but thinly documented and inconsistent in 2026
*#*#4636#*#* opens a Testing menu on many phones · *#0228# is a Samsung-specific battery code · neither is documented by Google or Samsung · checked 19 August 2026
The oldest, simplest method, and the weakest sourced. Neither Google nor Samsung documents these codes, so everything below rests on third-party reporting rather than on the vendors, and this page treats them accordingly.
Skip it if you want any actual capacity or health data, since neither code reliably provides it on 2026 software. Skip these entirely in favor of a native screen or AccuBattery, since dialer codes are not a real diagnostic route anymore.
The fallback that works on any phone
4.7 stars from 600,019 reviews · 10M+ installs · free to install, contains ads, in-app purchases $1.19 to $24.99 · by Digibites · Play listing updated 6 November 2025 · checked 19 August 2026 · Play listing
The standard third-party option for any phone without a native battery health screen, a Pixel 8 Pro included, since Android does not let apps read battery capacity directly.
Skip it if your phone already has a native Battery health screen, since that gives an exact number with none of the wait. Use it over dialer codes every time, since it is a real measurement rather than a hidden menu that mostly stopped working.
Battery Health Assistance
On the same screen as Battery health sits Battery health assistance. Google's own support page describes exactly what it does: "This software adjusts the battery's maximum voltage in stages. It starts at 200 charge cycles and continues gradually until 1000 charge cycles. This helps stabilize battery performance and aging." It is available on Pixel 6a and later, and the trade-off is stated plainly too: "you may notice a slight change in battery charging performance."
Whether to turn it off is a genuine trade-off, not a settled question, and on the newest Pixel it is not a choice at all. Google recommends leaving it on, and describes the cost in qualitative terms only: "you may notice small decreases in your battery's runtime" and "a slight change in battery charging performance." It publishes no figure for how much runtime you give up, so anyone weighing that trade-off is working without a number. Google's page states the exception directly: "On Pixel 9a and later, this feature is on by default and can't be turned off." Every other supported Pixel, 6a through 9 Pro Fold, has a toggle at Settings, Battery, Battery health, Battery health assistance.
Pairing this with the Charging optimization setting extends the same idea further: Google's own instructions are "Tap Battery, Battery health, Charging optimization. Turn on Use charging optimization," with a "Limit to 80%" option "to prioritize the long-term health of your battery." The same Google page adds a detail worth knowing if that 80% limit stays on permanently: the battery should still fully charge to 100% roughly every tenth cycle, so the fuel gauge's capacity readings stay accurate.
What the number means
Every method above reports the same underlying thing: current capacity as a percentage of design capacity. A few points trip people up. It is always an estimate: no sensor reads out remaining capacity directly, the fuel gauge chip infers it from voltage curves, current and temperature, so two tools can legitimately disagree by a few points on the same phone. Eighty percent is the industry service line, not a death sentence; below it, degradation accelerates and voltage sag starts causing real symptoms, but a phone at 82 percent still works, it just runs out earlier than it used to.
Capacity is not the same thing as battery life. A phone at 95 percent capacity with a runaway background app can die faster in a day than a well configured phone sitting at 82 percent. If runtime cratered suddenly rather than declining gradually over a year, software is the likelier culprit, and a sluggish phone often shares the same root causes covered in the guide to speeding up a slow Android phone.
What to actually do about it
Replace now if: capacity reads below 80 percent, the threshold Google itself uses to recommend replacement, and the phone no longer lasts the day; it shuts down well before reaching zero, a sign the voltage is sagging faster than the fuel gauge expects; the back cover bulges or the screen lifts, which means a swelling cell and a safety issue regardless of the percentage; or it runs hot during light use. A swollen cell can ignite when punctured, so that specific symptom calls for a repair shop, not a DIY attempt.
Change habits if: capacity is above roughly 85 percent and the real complaint is daily drain rather than physical aging. Fix the software first, then slow future aging: turn on the roughly 80 percent charging limit where the phone offers one, keep the phone out of heat while charging, prefer slow charging to repeated fast top-ups, and avoid routinely running the battery to zero.
In the gray zone, 80 to 85 percent, tighten those habits, recheck in two months, and budget for a replacement within the year. Batteries do not recover capacity once lost; the only real choice is how gently the decline is managed from here.
Google limited the feature to the Pixel 8a, Pixel 9 series, and newer. Google did not give a reason on its own support page; it reportedly told the press the cause was "product limitations" on older hardware. The Pixel 8 and 8 Pro are excluded even on Android 16. AccuBattery is the fallback for a capacity estimate on those models. Checked 19 August 2026.
Most people should leave it on: it trades a small amount of per-charge runtime for slower long-term aging. Turning it off suits someone who needs maximum runtime today and plans to replace the phone within a year or two. On the newest Pixel models it is mandatory with no off switch.
It is real and still opens a Testing menu on many phones, and Samsung's *#0228# is a genuine, separate code for battery status, but neither is officially documented by Google or Samsung, so exactly what data each shows varies by device and firmware version. The native settings screens or AccuBattery are the more consistent routes in 2026.
There is no single published figure, and it depends heavily on how the phone is charged and how hot it gets. The useful anchor is Google's own: it rates Pixel 8a and later to keep at least 80 percent capacity for about 1000 charge cycles, and earlier models for about 800. Dropping below 80 percent inside the first year is worth raising with the manufacturer, since some cover premature degradation under warranty.
On many models, yes, though glued back covers make it fiddly and the difficulty varies a lot by model, so check a teardown guide for your exact phone before ordering parts. If the battery is visibly swollen, stop and take it to a repair shop instead: a swollen cell can ignite when punctured.
Yes, measurably. Lithium cells age fastest at high voltage and heat, and sitting at 100 percent overnight is one of the more common habits that accelerates that aging. Google offers a "Limit to 80%" setting for exactly this reason, describing it as "ideal if you usually end the day with some charge left." The obvious cost is that you start the day with less charge; Google publishes no figure for how much cycle life it buys back.
Checked 19 August 2026: this page carried strong, specific technical detail already, but no source links, no dated verification, and no decision table, none of which met this site's sourcing standard. AccuBattery, named throughout, now has its own Play listing linked, and its real figures added: contains ads and gates some features behind $1.19 to $24.99 in-app purchases, which the previous text described only as "free." A first-person opinion aside has been rewritten in the third person to match the rest of the page's sourced, attributed style. Several specific Samsung and dialer-code claims, a "maximum capacity percentage" on Samsung's Battery information screen, Device Care's exact verdict wording, Samsung Members' rating scale, and *#0228# being blocked on One UI 8, could not be confirmed against any source reachable at the time of the deepest verification pass and have been replaced with what could actually be confirmed: cycle count and manufacture date on Samsung's screen, sourced to independent tech-press coverage since Samsung's own support site was unreachable, and both dialer codes' basic real-but-undocumented status. A decision table, an "Our answer" capsule, a dated verification box and this changelog are new; the underlying Pixel-specific technical explanations were already accurate and are preserved. Re-audited the same day: a claim sourced only to a tech-press headline nobody had actually read, about a writer losing trust in Samsung's on-device figure, has been removed as uncitable. The Galaxy S25 Battery information reporting is now linked to the article it came from rather than only named, and the Samsung Members diagnostic, previously the weakest-sourced item here, is now quoted from Samsung's own Play listing for that app. Two AccuBattery specifics carried over from the older draft, a rule about only counting charges above 60 percent and a one-to-two-week settling period, appear in neither its Play listing nor the developer's own site, so they have been replaced by what those sources do state about how it measures. A further adversarial pass the same day caught the biggest problem on the page: the Pixel screen was described as giving "an exact capacity percentage rather than an estimate," when Google says the opposite in the very page cited, "Capacity is estimated by the battery's fuel gauge," and this page's own later section already said the same. That is corrected throughout, along with the menu path, which stops one tap short of where the number actually lives. Several other figures stated flatly with no source, a typical first-year capacity range, the share of runtime an 80 percent cap costs, a shutdown threshold and a repair-difficulty rating, have been replaced with what Google does publish or removed. The Samsung section no longer claims a One UI version number no source gave, and now reports that the same launch coverage found the screen showing different fields on different units.
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