How to Check and Improve Smartphone Battery Health
Degradation is unavoidable — but how fast it happens is mostly decided by habits, not luck.
Battery health isn't just a number to glance at once — it's the single biggest factor in how long your phone lasts before it starts feeling sluggish, shutting down unexpectedly, or needing a charger nearby at all times. Every lithium-ion battery degrades gradually with normal use; that part is unavoidable. But how fast it degrades is largely shaped by daily charging habits most people never think about. This guide covers how to check your battery's real condition on both Android and iPhone, what those numbers actually mean, and which habits genuinely slow the decline versus which ones are internet myths.
Why Batteries Degrade in the First Place
Every phone battery is rated in charge cycles, where one full cycle equals using 100% of the battery's capacity — whether that happens in a single day or spread across a week of partial charges. Manufacturers typically design batteries to retain a large majority of their original capacity after several hundred full cycles under normal conditions, after which capacity decline accelerates. The chemistry itself is the limiting factor — no software trick fully stops it — but heat, charge extremes, and fast-charging frequency all directly influence how quickly you burn through that cycle life.
Signs Your Battery Health Is Already Declining
Before checking any number in Settings, a few everyday symptoms are usually the first real clue something has changed: the phone losing a noticeably larger chunk of charge overnight while barely used, the battery percentage jumping suddenly from a moderate number straight to a shutdown warning, or the phone feeling warm during light, everyday tasks that never used to cause it. None of these confirm degraded battery health on their own, since background apps or a recent software update can cause similar symptoms temporarily, but if they persist for more than a couple of weeks, it's worth checking the battery health percentage directly rather than assuming it will resolve on its own.
Checking Battery Health on Android
AndroidOpen your phone's built-in battery health section
Many recent Android phones include a battery health section directly in Settings, typically under Settings > Battery > Battery health or a similarly named menu. This shows an estimated battery capacity percentage relative to when it was new, along with a general health rating. Availability varies significantly by manufacturer and Android version — if you don't see it immediately, check your phone maker's own diagnostics or companion app instead.
AndroidUse manufacturer diagnostic tools for a second opinion
Samsung phones can run a battery diagnostic through the Samsung Members app, which reports both battery status and a general health estimate. Other manufacturers offer similar built-in diagnostic tools under their own device-care or system-health apps. These are generally more detailed than a plain settings menu and worth checking if your phone doesn't expose a battery health percentage directly.
AndroidCheck your usage graph for context
Beyond the health percentage itself, checking Settings > Battery and reviewing the usage graph gives useful context — a battery that seems to be draining unusually fast may point to a specific app running excessive background activity rather than genuine battery degradation. It's worth ruling that out before assuming the battery itself is the problem.
Checking Battery Health on iPhone
iPhoneOpen Battery Health and Charging
Go to Settings > Battery > Battery Health & Charging. This shows your Maximum Capacity as a percentage compared to when the battery was new — the clearest single number iOS provides for tracking degradation over time. Apple's own guidance treats a battery below roughly 80% maximum capacity as showing meaningfully reduced performance, though the point where you'll actually notice a difference varies by how you use the phone.
iPhoneCheck for a Peak Performance Capability notice
On the same screen, iOS displays a note if the battery's condition is significantly degraded and performance management has been applied to prevent unexpected shutdowns during peak power demands. If you see this message, it's a stronger signal than the percentage alone that the battery is genuinely affecting how the phone performs, not just how long it lasts between charges.
iPhoneReview battery usage by app
Under Settings > Battery, scrolling down shows a breakdown of usage by app over the last 24 hours or 10 days. As with Android, a battery that seems to degrade unusually fast is sometimes actually a specific app consuming disproportionate background power — worth checking before assuming it's a hardware issue.
Habits That Genuinely Slow Degradation
Keep the phone out of high heat
Heat is the single most damaging factor to lithium-ion battery longevity, more so than charging habits in most real-world cases. Leaving a phone in direct sun, a hot car, or under a case while gaming and charging simultaneously accelerates degradation measurably faster than almost any other single habit. If your phone ever feels noticeably hot to the touch, that's worth addressing before it becomes routine.
Avoid sitting at 100% for long periods
A battery held at full charge for extended periods experiences more chemical stress than one that spends most of its time in a moderate charge range. Both Android and iOS now offer optimized or adaptive charging features that learn your daily routine and delay the final charge to 100% until shortly before you typically unplug, specifically to reduce this kind of prolonged full-charge stress. Enabling this is one of the few genuinely evidence-backed settings worth turning on.
Use certified or original charging accessories
Off-brand chargers and cables that don't meet a phone's expected power-delivery specifications can deliver inconsistent voltage, generating more heat during charging than a properly matched charger. This isn't about brand loyalty — any charger genuinely certified for your phone's charging standard works fine — but a low-cost, uncertified cable is a real, often overlooked, source of extra heat.
Don't chase 0% or 100% as daily targets
Letting a battery regularly drain to empty before recharging, or always topping it back up to a full 100%, both add more cumulative stress than keeping the battery in a broader middle range during normal daily use. This doesn't mean obsessively unplugging at a specific number — simply not letting the phone sit at either extreme for extended periods is enough to make a meaningful difference over months of use.
Store a spare phone at partial charge
If you're storing a phone for weeks or months without using it — a backup device or an old phone kept as a spare — leaving it at 100% or fully drained during long-term storage causes more degradation than storing it at a moderate charge level, generally cited as somewhere around 50%, and checking on it periodically rather than leaving it untouched for months at a time.
Habits That Make Little Real Difference
Closing background apps to "save" the battery
Manually force-closing apps throughout the day is a widely repeated habit that generally does little for battery health specifically, since modern operating systems already manage background app activity efficiently, and reopening an app from scratch often uses more power than resuming it from the background. This affects daily battery drain more than long-term degradation, and even then, the effect is usually smaller than expected.
Using battery saver mode constantly "just in case"
Battery saver modes reduce background activity and some performance to extend a single charge, which is useful when you're actually running low, but running it permanently doesn't meaningfully slow the underlying chemical degradation of the battery itself — it only affects how long each individual charge lasts, not the battery's long-term capacity curve.
Are Third-Party Battery Apps Worth Installing?
Most third-party battery apps read the same underlying system data your phone's own battery settings already expose, just presented with extra charts or a slightly different capacity estimate — they don't have access to any deeper hardware diagnostic the built-in tools lack. For most people, the native battery health screen on iPhone, or a manufacturer's own diagnostic tool on Android, is enough, and installing a separate app mainly adds another background process running on the very battery you're trying to protect. A third-party app is worth considering only if your specific phone doesn't expose any battery health information natively at all.
When to Consider a Battery Replacement
If your battery health percentage has dropped into a range where you're noticing real-world effects — unexpected shutdowns, the phone struggling to make it through a normal day, or a Peak Performance Capability notice on iPhone — a battery replacement is usually the more sensible fix rather than replacing the entire phone. Battery replacement is typically far less expensive than a new device, and for phones you're otherwise still satisfied with, it can meaningfully extend the phone's useful life for a fraction of the cost of upgrading.
Note: Exact menu names, available diagnostics, and specific capacity thresholds vary by manufacturer and OS version. If a setting mentioned here isn't exactly where described, search your Settings app using the bolded keyword from that step.
FAQ
What's a normal battery health percentage after one year of use?
It varies significantly by usage pattern, but a healthy battery after roughly a year of typical daily charging is generally still well above the range where users start noticing real performance effects. The specific number depends heavily on how the phone was charged and used, so context matters more than the number alone.
Does fast charging damage my battery faster than slow charging?
Fast charging does generate more heat than slower charging, and heat is the primary factor in degradation, so relying on fast charging for every single charge is somewhat harder on the battery than occasional slower charging. For most people the convenience is worth it, and optimized charging features help offset the difference.
Is it bad to charge my phone overnight?
Modern phones with optimized or adaptive charging features are specifically designed to handle overnight charging safely, pausing near full charge and completing the final percentage closer to when you typically wake up — which largely addresses the old concern about sitting at 100% all night.
Can a software update fix a degraded battery?
No — degradation is a physical, chemical process, and no software update can restore lost capacity. Some updates can adjust how the phone manages power around an already-degraded battery, but that manages symptoms rather than reversing the underlying capacity loss.
Should I remove my phone case while charging?
If your phone tends to run warm during charging, especially while also being used for something demanding like gaming, removing a thick case can help heat dissipate faster. For normal charging at a moderate room temperature, it typically makes little practical difference.
Bottom line: Check your battery health first using your phone's built-in tools so you have an actual baseline rather than guessing. Enable optimized or adaptive charging if your phone offers it — it's the single easiest habit change with real evidence behind it. Keep the phone away from serious heat, avoid parking it at either extreme for long stretches, and skip habits that sound helpful but don't meaningfully affect long-term degradation, like obsessively closing background apps. If your battery health has genuinely dropped enough to affect daily use, a replacement is usually the more sensible move over a full upgrade.
For more device maintenance tips, browse our Android coverage or our how-to guides.