Your phone dies by mid-afternoon or your laptop drops from 40% to zero without warning. Before you blame an update or start shopping for a new device, check the battery’s health: every major platform now reports it, and the number tells you whether a cheap battery swap will fix the problem.
Below are the exact steps for iPhone, Google Pixel, Samsung Galaxy, Mac and Windows laptops, followed by a simple rule for deciding when to replace the battery and when to replace the device.
What “battery health” actually measures
Lithium-ion batteries lose capacity as they age. Health readouts compare how much charge the battery can hold today with what it held when new. A phone showing 85% can store roughly 85% of its original energy, so a full charge lasts about 15% less than it did out of the box.
The other number that matters is the charge cycle count. One cycle equals using 100% of the battery’s capacity, but not necessarily in one go. Draining from 100% to 50% twice adds up to one cycle. Manufacturers rate batteries to keep about 80% of their capacity for a set number of cycles, and that rating is your best guide to how much life is left.
How to check battery health on iPhone
- Open Settings and tap Battery.
- Tap Battery Health (on some iOS versions, Battery Health & Charging).
- Read Maximum Capacity and the Peak Performance Capability message.
Apple says iPhone 14 models and earlier are designed to keep 80% of their original capacity at 500 complete cycles, while iPhone 15 models and later are designed for 80% at 1,000 cycles, both under ideal conditions. A brand-new iPhone can show slightly under 100% depending on how long it sat between manufacture and activation, so 99% on day one is not a defect.
Pay attention to the performance message. If it says performance management has been applied after an unexpected shutdown, iOS is throttling the phone to prevent more shutdowns. A “significantly degraded” message means Apple recommends a replacement. If you see “Unable to verify,” the battery may be non-genuine and the health figure may not be accurate.
How to check battery health on Google Pixel
On the Pixel 8a and later, Google shows both health and cycle count:
- For health: open Settings > Battery > Battery health. You will see “Normal” or “Reduced” plus an estimated capacity.
- For cycle count: open Settings > About phone > Battery information. This screen also shows the battery’s manufacture date and date of first use.
Google’s Pixel battery help page rates the Pixel 8a and later for about 1,000 cycles at 80% capacity, and the Pixel 3 through Pixel 8 Pro and the original Pixel Fold for about 800. Models in that second group do not show a battery health status, and the feature is not available on Pixel Tablet. If your Pixel shows “Reduced,” Google recommends replacing the battery.
How to check battery health on Samsung Galaxy
Samsung’s official route goes through the Samsung Members app, which is preinstalled on most Galaxy phones:
- Open Samsung Members and tap Support.
- Tap Get started under phone diagnostics.
- Choose Battery status and read the result.
According to Samsung’s support guide, Galaxy phones may also display a battery performance degradation alert when capacity drops significantly, and Samsung’s advice is to get the battery inspected at a service centre. Menu names vary by model and One UI version, and some recent Galaxy models have started showing more detail in the Settings app’s battery section. If you don’t see it there, Samsung Members is the reliable fallback.
How to check battery health on a Mac
- Open the Apple menu > System Settings > Battery.
- Click the info button next to Battery Health. You will see “Normal” or “Service Recommended.”
- For the cycle count, hold Option, choose System Information from the Apple menu, select Power and read Cycle Count.
Apple’s published cycle count table rates most Mac laptops from the past decade, including every Apple silicon MacBook Air and MacBook Pro, at 1,000 cycles. Some much older models are rated for 300 or 500. Apple considers the battery consumed at that count, though the Mac keeps working with shorter runtime. “Service Recommended” does not mean the Mac is unsafe to use.
How to check battery health on Windows
Windows has no health percentage in Settings, but it can generate a detailed report:
- Right-click Start and open Terminal or Command Prompt.
- Type
powercfg /batteryreportand press Enter. - Open the HTML file it saves (the path is shown in the output, usually your user folder).
- Under Installed batteries, compare Design Capacity with Full Charge Capacity, and note Cycle Count if your laptop reports it.
Microsoft documents the command and its options, such as /output to choose the file location, in its powercfg reference. The report doesn’t calculate health for you, so do the maths yourself.
Worked example: a laptop with a design capacity of 56,000 mWh and a full charge capacity of 44,800 mWh has 44,800 Ă· 56,000 = 80% health. If it used to last eight hours, expect about six and a half now, before accounting for any extra drain from newer software. Laptop makers such as Dell, Lenovo and HP also include battery health readouts in their own support apps, which can be easier than the report.
At a glance: where to look and what is normal
| Device | Where to check | Rated cycles to 80% |
|---|---|---|
| iPhone 14 and earlier | Settings > Battery > Battery Health | 500 |
| iPhone 15 and later | Settings > Battery > Battery Health | 1,000 |
| Pixel 3 to Pixel 8 Pro, Pixel Fold | Not shown in Settings on these models | About 800 |
| Pixel 8a and later | Settings > Battery > Battery health | About 1,000 |
| Samsung Galaxy | Samsung Members > Support > Battery status | Not published in the same format |
| Recent MacBooks | System Settings > Battery | 1,000 |
| Windows laptops | powercfg /batteryreport | Varies by manufacturer |
Replace the battery or replace the device?
Here is the decision rule we use. It assumes the device is otherwise working and still gets software updates.
| Situation | Our recommendation |
|---|---|
| Health above 85%, battery life still poor | The battery is not the problem. Look for a rogue app, background sync or screen brightness settings |
| Health 80-85%, cycles near the rating | Plan a replacement within months, especially before winter. Cold weather exposes weak batteries |
| Health below 80%, “Reduced,” “Service Recommended” or unexpected shutdowns | Replace the battery. It is almost always cheaper than a new device |
| Battery is degraded and the device no longer gets security updates | Replace the device. A new battery will not fix the security risk |
| Swollen battery, bulging case or a screen lifting off the frame | Stop using and charging it and take it to a repair shop now |
One practical point: get the replacement from the manufacturer or an authorized repair partner where possible. Apple specifically warns that third-party batteries can trigger the “Unable to verify” message, and you lose an accurate health readout from then on.
How to slow the decline
- Turn on charge limiting. iPhone, Pixel, Samsung and Mac all offer optimized or capped charging that keeps the battery away from 100% for long stretches.
- Avoid heat. Heat is the fastest way to age a lithium-ion cell. Don’t charge under a pillow or leave a phone on a car dashboard. Google suggests charging somewhere around 25°C.
- Use a decent charger. A certified USB-C Power Delivery charger is safer and kinder to the battery than a no-name brick.
- Check twice a year. Note health and cycle count in your calendar, so you see the trend instead of being surprised by it.
If the numbers say it’s time for a new device rather than a new battery, our smartphone buying guide covers what to prioritise, and our comparisons of Android vs iOS and laptop vs tablet can help you decide what to buy next.
