How to Check Laptop Battery Health (Windows & Mac)
Quick answer: To check laptop battery health, compare its current full-charge capacity to its original design capacity. On Windows, run a battery report from the command line; on Mac, check Battery Health in settings. Below about 80% after a couple of years is normal wear.
Battery health is the ratio of a battery's current full-charge capacity to its original design capacity, expressed as a percentage. A new battery reads 100%. Most manufacturers treat anything below about 80% as worth replacing, and that threshold is usually reached somewhere between 500 and 1,000 charge cycles.
For a quick live look at charge level and charging status, open the battery test.
Check battery health on Windows
Open Command Prompt and run powercfg /batteryreport. It saves an HTML file (the path is shown); open it and compare Full Charge Capacity with Design Capacity. The gap is your wear, and the report also shows the cycle count and recent usage. You can run the same command from Windows Terminal, and the report also charts recent usage and how capacity has fallen over time.
Check battery health on Mac
Go to System Settings → Battery → Battery Health (or hold Option and click the battery icon on older versions). It shows a status of Normal or Service Recommended, and the cycle count appears in System Information under Power. macOS also offers Optimized Battery Charging, which holds the charge below 100% until you need it to slow wear, and the full cycle count is listed under System Information → Power.
Quick live check
The browser battery test shows what your browser reports — charge level and whether you are plugged in — where the device and browser expose it.
Why battery health matters
Every rechargeable battery wears down over time, holding less charge than when it was new — this is normal and unavoidable. Battery health is a measure of how much capacity remains compared with the original design capacity, expressed as a percentage. A battery at 90% health holds about 90% of what it once did; one that's dropped to 70% will run noticeably shorter on a charge. Checking your battery's health tells you whether short run-times are down to wear, whether a replacement is worth considering, and how your charging habits are affecting it over time. Both Windows and macOS have built-in ways to see it.
When to replace and how to prolong it
As a rough guide, once a battery falls to around 80% health or below, or you're getting frustratingly short run-times, it's worth considering a replacement — and many manufacturers consider significant capacity loss within the warranty period a valid claim. To prolong battery life, avoid keeping it at extremes: regularly draining to 0% or sitting at 100% for long periods both add wear, so keeping it roughly between 20% and 80% is gentler. Heat is a battery's enemy, so avoid leaving a laptop charging in hot places or blocking its vents. Use optimised or limited charging features if your laptop offers them. None of this stops wear entirely — it's a normal part of a battery's life — but good habits meaningfully slow it down. Our battery test helps you observe how your battery discharges in real use.
Understanding cycle counts and wear
A charge cycle is one full discharge and recharge worth of capacity — but it doesn't have to happen in one go. Using half your battery, recharging, and using half again the next day counts as a single cycle, not two. This matters because batteries are rated for a number of cycles (often several hundred to around a thousand on modern laptops) before their capacity is expected to drop noticeably, so the cycle count is a good gauge of how much life a battery has used up. You can find it in the Windows battery report and in macOS System Information. A laptop with a low cycle count but poor health may have been damaged by heat or sitting at full charge, while a high cycle count with decent health simply reflects heavy but healthy use. Occasionally letting the battery run down and recharge fully can also help the system recalibrate its capacity estimate so the percentage shown is accurate. Mac laptops are typically rated near 1,000 cycles, and most batteries reach roughly 80% of design capacity after a few hundred — expected wear rather than a fault.
Sources: MDN — Battery Status API · Apple — Determine battery cycle count for Mac laptops
Frequently asked questions
How do I check my laptop battery health on Windows 11?
Open Command Prompt and type powercfg /batteryreport, then press Enter. Windows saves an HTML report to your user folder. Open it and compare Full Charge Capacity to Design Capacity — dividing one by the other gives your battery health percentage.
How do I check battery health on a Mac?
On macOS, go to System Settings → Battery and click the information (i) icon next to Battery Health to see the status and maximum capacity. The cycle count is in System Information under Power. Optimized Battery Charging helps slow wear.
When should I replace my laptop battery?
As a rough guide, once health drops to around 80% or below, or run-times become frustratingly short, consider a replacement. Significant capacity loss within the warranty period may also be a valid warranty claim worth pursuing with the maker.
How can I make my laptop battery last longer?
Avoid extremes — regularly hitting 0% or sitting at 100% for long periods both add wear, so keeping it roughly between 20% and 80% is gentler. Keep it cool, avoid charging in hot places, and use optimised charging features if available.
What is a battery cycle count?
A charge cycle is one full battery's worth of use, which can build up over several partial charges — using 50% twice equals one cycle. Batteries are rated for a set number of cycles before capacity drops noticeably, so the count shows how much life has been used.
Is it bad to leave my laptop plugged in all the time?
Sitting at 100% for long periods adds wear, especially with heat. It won't overcharge, since charging stops when full, but keeping it constantly topped up isn't ideal. Use optimised charging if available, or unplug occasionally to let it cycle between roughly 20% and 80%.
Test it yourself: Battery Test · Phone Sensor Test