Battery Health Check: How to See Real Battery Wear

A battery health check tells you how much charge your battery can still hold compared with when it was new. That number, usually called maximum capacity or full charge capacity, is what really decides how long your phone or laptop lasts. A web page cannot read it: browsers only expose the current level and charging state, which is what our battery test shows. The real health figure lives in your operating system, and below you will find where to look on every platform, how to read the result and what to do next.

iPhone

Open Settings › Battery › Battery Health & Charging (on some iOS versions the item is simply called Battery Health).

• Maximum Capacity is the capacity relative to new. 100% is a new battery.
• Peak Performance Capability says whether the phone is limiting performance to avoid unexpected shutdowns.
• On iPhone 15 and later you can also see the cycle count, manufacture date and first use, under the battery health screen or in Settings › General › About.

Apple rates iPhone 14 and earlier for about 80% capacity after 500 full cycles, and iPhone 15 and later for about 80% after 1,000 cycles. If the screen shows a "Service" message, the battery is significantly worn.

Android

Android has no single battery health screen; it depends on the manufacturer.

• Samsung Galaxy: open the Samsung Members app, go to its support or diagnostics section and run the Battery status check. It reports whether battery life is normal or weak.
• Google Pixel: on Pixel 8a and newer, go to Settings › Battery › Battery health. Cycle count and manufacture date are shown under Settings › About phone › Battery information. Older Pixels do not show a health figure.
• Other brands (Xiaomi, OnePlus, Oppo, Motorola…): search Settings for "battery health" or use the maker's support or diagnostics app.

You may read about dialing *#*#4636#*#*. On many phones it opens a testing menu, but on recent Android versions the battery line is often missing or only says "Good", which is not a capacity measurement. Do not rely on it.

Windows laptops: the battery report

Windows has a built-in battery report.

1. Right-click the Start button and open Terminal (or Command Prompt).
2. Type powercfg /batteryreport and press Enter.
3. Windows saves a file called battery-report.html and prints its path, usually your user folder. Open it in any browser.

Under Installed batteries, compare Design capacity with Full charge capacity. Divide full charge by design capacity and multiply by 100: 42,000 mWh out of 56,000 mWh means 75% health. The same table shows Cycle count on most laptops. Further down, Battery capacity history shows how capacity has fallen over time, and Battery life estimates compares current runtime with what the battery delivered when new.

Many laptop makers also ship their own tool (Lenovo Vantage, Dell, HP or ASUS support apps) that shows the same data with a simple good/fair/poor rating.

macOS

Open Apple menu › System Settings › Battery. Next to Battery Health, click the info button. It says Normal or Service Recommended, and recent macOS versions on Apple silicon also show the maximum capacity percentage.

For the cycle count, hold the Option key, click the Apple menu and choose System Information, then select Power in the sidebar. You will see Cycle Count and Condition. Most modern MacBooks are rated for 1,000 cycles.

Linux (short)

Run upower -i $(upower -e | grep BAT) in a terminal. Compare energy-full with energy-full-design; the capacity line already gives the percentage. On systems without upower, the same values are in /sys/class/power_supply/BAT0/.

How to read your battery health result

• Above 90%: healthy. Normal for a device up to a year or two old.
• 80–90%: normal wear. You will notice a shorter day, but there is no need to act.
• Below 80%: the battery is considered worn. Most manufacturers treat 80% as the end of a battery's rated life, and runtime drops noticeably.
• Cycle count shows how much the battery has been used. One cycle is 100% of capacity used in total, not necessarily in one go: two days at 50% each make one cycle.

A few caveats. Health readings come from the battery's own chip and are estimates; they can move by a few percent after a full charge and discharge. A new laptop may even show slightly more than 100%. Look at the trend, not one reading. And remember that our browser battery test shows the level, not the health: a level that falls quickly or jumps from 30% to 5% is a symptom, while the figures above show the cause.

Battery draining fast? 10 things to check

1. Find the culprit app. On phones, Settings › Battery lists usage by app. On Windows use Settings › System › Power & battery; on a Mac, the Energy tab in Activity Monitor.
2. Lower screen brightness and turn on automatic brightness. The display is usually the biggest consumer.
3. Use a lower refresh rate. 120 Hz looks smooth but costs battery; 60 Hz or an adaptive setting saves power.
4. Limit background activity. Restrict background refresh, sync and location access for apps that do not need it.
5. Watch the signal. Weak mobile coverage makes the modem work harder. Prefer Wi-Fi, or use airplane mode where there is no signal.
6. Give updates time. After a major system update the phone indexes and optimises in the background for a day or two.
7. Turn on power saving. Low Power Mode, Battery Saver or the "Best power efficiency" power mode on Windows.
8. Check startup and background apps on laptops, and close browser tabs that run heavy pages or video.
9. Keep it cool. Heat drains and wears batteries. Avoid charging under a pillow, in a hot car, or in a thick case while gaming.
10. Restart and check the health figure. If drain stays high after a restart and health is below 80%, the battery itself is the problem.

When to replace the battery

Replace the battery when maximum capacity is below about 80% and the runtime no longer gets you through your day, when your phone or Mac shows a service message, or when the device shuts down suddenly at 20–30% charge.

Stop using the device at once if the battery is swollen: the case bulges, the screen lifts or the trackpad no longer clicks properly. Do not charge it or press on it, and take it to a repair service. For iPhones, Macs and most laptops, an official or authorised service centre uses a genuine battery and keeps health reporting accurate.

To slow future wear: avoid heat, do not leave the device at 100% or 0% for long periods, and use the optimised or limited charging option your system offers.

Frequently asked questions