How to Check Laptop Battery Health (Windows, Mac and Chromebook)

If your laptop no longer lasts as long on a charge, it helps to know how to check laptop battery health before you blame an app or buy a new machine. Every laptop battery wears out slowly as it charges and discharges, and each system has a built-in way to show how much capacity is left. This guide covers Windows, Mac and Chromebook, explains what the numbers mean, and tells you when a replacement makes sense and when a battery is unsafe to use.

This is an independent guide, not affiliated with Microsoft, Apple, Google or any laptop maker. For warranty or battery service, use your laptop maker’s own support site.

Windows: create a battery report

Windows has a hidden but reliable tool called the battery report. It works on Windows 11 and Windows 10.

1. Right-click the Start button and choose Terminal (on Windows 10, search for Command Prompt).
2. Type powercfg /batteryreport and press Enter.
3. Windows replies with the location of the saved file, usually C:\Users\YourName\battery-report.html.
4. Open File Explorer, go to that folder and double-click battery-report.html. It opens in your web browser.

If you want the file somewhere easier, you can add an output path, for example powercfg /batteryreport /output "%USERPROFILE%\Desktop\battery-report.html".

What to look for in the report

Item	What it means
Design Capacity	How much energy the battery held when new, in mWh
Full Charge Capacity	How much it holds now when fully charged
Cycle Count	How many full charge cycles it has gone through (some laptops leave this blank)
Battery capacity history	How full charge capacity has changed over recent weeks
Battery life estimates	How long the battery lasted on recent charges compared with when new

To get a rough health figure, divide Full Charge Capacity by Design Capacity and multiply by 100. For example, 40,000 mWh out of a 50,000 mWh design capacity is 80% of the original capacity. A brand-new battery can read slightly above or below 100%; that is normal.

Windows Settings

Settings > System > Power & battery shows the current charge, battery usage by app and power mode options. It is useful for finding apps that drain the battery, but on most laptops it does not show battery wear, so the battery report is the better health check. Many laptop makers also include their own app (for example a support or “vantage” style utility) that shows battery condition and may offer a charge limit setting.

Mac: Battery Health and cycle count

On a Mac laptop with a recent version of macOS:

1. Open the Apple menu > System Settings and select Battery in the sidebar.
2. Next to Battery Health, select the Info button (the small “i”).
3. You will see the condition, such as Normal or Service Recommended, and on many models a Maximum Capacity percentage.

To see the cycle count, hold the Option key, open the Apple menu and choose System Information. Under Hardware, select Power and look under Battery Information.

Apple publishes the maximum cycle count for each Mac laptop. Recent models are rated for 1000 cycles, and Apple says a normal battery is designed to retain up to 80% of its original capacity at its maximum cycle count. A charge cycle means using 100% of the battery’s capacity in total, not necessarily in one go: using half one day and half the next counts as one cycle.

Chromebook: the Diagnostics app

Chromebooks include a Diagnostics app. Open the launcher and search for Diagnostics, or go to Settings > About ChromeOS > Diagnostics. The Battery section shows battery health, cycle count and the current charge or discharge rate, and you can run a charge or discharge test. Menu names can differ slightly between ChromeOS versions; searching the launcher is the quickest route.

Habits that help a battery last

• Avoid heat. Heat is hard on batteries. Do not use the laptop on a bed or cushion that blocks the vents; see our guide on a laptop overheating and shutting down.
• Use smart charging features. Macs have Optimized Battery Charging, and many Windows laptops offer a charge limit in the maker’s app. These reduce time spent at 100%.
• Don’t store it flat or full for long periods. If you put a laptop away for weeks, leave the battery partly charged.
• Keep the system updated. Firmware and power management updates can improve charging behavior.
• Use a proper charger. Use the original charger or one that matches the laptop maker’s specifications.

When to replace the battery

There is no single magic number. Consider a replacement when:

• The laptop no longer lasts long enough for how you use it.
• macOS shows Service Recommended, or the Windows report shows a full charge capacity far below design capacity.
• The laptop shuts off suddenly at a reported 20% or 30% charge.
• The battery has reached the maker’s rated cycle count.

If the laptop is plugged in but the battery will not charge at all, that may be a charger, port or setting problem instead; see laptop plugged in but not charging. For a laptop that is slow as well as short on battery, try speeding up a slow laptop first. Battery replacement is best done by the laptop maker or a reputable repair shop, especially on models where the battery is glued in.

Warning: swollen batteries

A lithium-ion battery that is swelling is a safety hazard. Signs include a trackpad that no longer clicks properly, a case that bulges or no longer sits flat, a gap between the screen and body, or a keyboard that lifts.

If you see any of these:

1. Stop using and stop charging the laptop. Unplug it and shut it down.
2. Do not press, puncture or try to remove the battery yourself.
3. Keep it on a hard, non-flammable surface away from anything that can burn.
4. Take it to the maker’s service or a repair shop. For disposal, use a battery recycling drop-off, never household trash.

For more help with laptops and other devices, browse the hardware topic hub.