Check battery health using your operating system's built-in tools
Both Windows and macOS include free tools that show you exactly how your battery is performing right now. You do not need to read anything or pay for software — the information is already on your machine.
On Windows 10 or 11, open Command Prompt as administrator (right-click the Start menu, select "Windows Terminal (Admin)" or "Command Prompt (Admin)"), then type this command and press Enter:
powercfg /batteryreport
Windows generates an HTML file and tells you where it saved it — usually in your user folder. Open that file in your browser. The report shows your design capacity (what the battery held when new), full charge capacity (what it holds now), and cycle count (how many times it has fully charged and discharged). If full charge capacity is below 80 percent of design capacity, your battery is degrading.
On macOS, hold Option and click the battery icon in the top-right corner of your screen. You will see a "Condition" line that reads "Normal", "Replace Soon", "Replace Now", or "Service Battery". Normal means your battery is healthy. Any other message means the battery is wearing out faster than it should.
Key Takeaways
- Windows Command Prompt generates a battery report showing design capacity, current capacity, and cycle count — compare the two capacities to see how much your battery has degraded.
- macOS Option-click on the battery icon shows a one-word condition status that tells you whether your battery needs replacement soon.
- A battery at 80 percent of its original capacity is still usable but will lose charge faster than when new.
- Batteries degrade with every charge cycle, and heat accelerates that process — keeping your laptop cool extends battery life.
Understand what the numbers mean
The Windows battery report gives you three key figures. Design Capacity is the amount of energy your battery was built to hold — this number never changes. Full Charge Capacity is what your battery actually holds right now after all the charging cycles it has been through. Cycle Count is how many times the battery has fully charged and discharged.
Divide full charge capacity by design capacity and multiply by 100 to get a percentage. If design capacity is 50 Wh and full charge capacity is 40 Wh, your battery is at 80 percent health. Most laptop batteries start losing noticeable performance around 70 to 80 percent health. At 50 percent health, the battery will drain noticeably faster and may not power the laptop through a full workday.
Cycle count tells you how much use the battery has seen. A typical laptop battery is rated for 300 to 500 full cycles before it drops to 80 percent capacity. If your cycle count is 200 and your capacity is already at 70 percent, heat or charging habits may be wearing the battery faster than normal. If your cycle count is 500 and capacity is at 85 percent, your battery is aging well.
Check battery health on older Windows versions
If you are running Windows 7 or an older version of Windows 10, the battery report command still works the same way. Open Command Prompt as administrator and type powercfg /batteryreport, then press Enter. The file will be saved in the same location and contain the same information.
If Command Prompt does not work or you prefer a visual tool, you can also check battery status through Settings. Go to Settings > System > Battery and Device Health (or Battery in older versions). This screen shows your current charge percentage and estimated remaining time, but it does not show design capacity or cycle count — the Command Prompt report is more detailed.
Look for signs of battery damage beyond the numbers
The capacity and cycle count tell you how much the battery has aged, but physical damage or manufacturing defects show up differently. If your laptop feels hot to the touch during normal use, the battery may be working harder than it should. If the battery drains from 100 percent to 0 percent in an hour or less during light use, the battery is failing faster than age alone would explain.
Swelling is a serious sign. If your laptop keyboard feels uneven, the trackpad is raised, or the bottom case is bulging, the battery may be swelling and pushing against the case from inside. Stop using the laptop and do not leave it plugged in — a swollen battery can overheat. Take it to a repair shop or contact the manufacturer. Do not try to remove the battery yourself unless you are experienced with laptop repair.
Understand what causes battery degradation
Lithium batteries lose capacity every time they charge and discharge, but some conditions speed up that loss. Heat is the biggest factor — a battery that spends most of its time above 80 degrees Fahrenheit will degrade much faster than one kept cool. If your laptop runs hot, make sure the vents are clear of dust and the laptop is on a hard surface, not a pillow or blanket that blocks airflow.
Charging habits also matter. Leaving your laptop plugged in all day, every day, keeps the battery at 100 percent charge, which stresses lithium cells. If you use your laptop mostly at a desk, unplug it once a day and let it drain to 20 or 30 percent before plugging back in. This is not required for the battery to work, but it slows degradation. Modern laptops have built-in charging limits that help — some stop charging at 80 percent if you leave them plugged in — but the feature must be turned on in your power settings.
Decide whether to replace the battery
If your battery is at 80 percent health and you use your laptop plugged in most of the time, you may not need to replace it yet. If you travel often or work away from outlets, a battery at 80 percent will give you noticeably less runtime than when new, and replacement may be worth the cost.
Replacement cost depends on your laptop model. Some laptops have user-replaceable batteries that cost $30 to $80 and take five minutes to swap. Others require disassembly by a technician and cost $100 to $300 in labor plus the battery itself. Check your laptop's manual or contact the manufacturer to find out which type you have and what the battery costs.
If your battery is below 50 percent health, replacement is usually the better choice than buying a new laptop — unless the laptop is also old and slow. A new battery can extend the life of a three- or four-year-old laptop by another two years.
Frequently Asked Questions
How often should I check my battery health?
Check it once every six months if you use your laptop daily, or once a year if you use it occasionally. You do not need to check more often — battery degradation is gradual and you will not see meaningful changes week to week. If you notice the laptop draining faster than usual, that is a good time to run a report and see if the battery has degraded suddenly.
Is it bad to leave my laptop plugged in all the time?
It will not damage the laptop, but it will degrade the battery faster than unplugging it regularly. Modern laptops have charging limits that reduce stress, but they work best if you unplug the laptop at least once a day. If you use your laptop at a desk and rarely move it, unplugging it for a few hours each day will extend battery life noticeably.
What does "Replace Soon" mean on a Mac?
It means your battery capacity has dropped to a point where Apple recommends replacement, usually around 80 percent health or lower. The laptop will still work, but the battery will not hold a charge as long as it did when new. You can continue using it until the battery drains faster than you find acceptable, then schedule a replacement.
Can I improve my battery health after it has degraded?
No. Battery degradation is permanent — once a lithium cell loses capacity, that capacity does not return. You can slow future degradation by keeping the laptop cool and unplugging it regularly, but you cannot restore capacity that has already been lost. Replacement is the only way to get full battery performance back.
Why does my battery report show a different capacity than my laptop's original specs?
Manufacturers round their battery capacity numbers for marketing. Your laptop might be advertised as having a "50 Wh" battery, but the actual capacity might be 49.2 Wh or 50.8 Wh. The report shows the true number. This is normal and not a sign of a defective battery.