How to Check Laptop Battery Health (Windows & Mac)

Why "it feels weaker" is not enough to go on

Every laptop battery loses capacity over time ÔÇö that part is unavoidable chemistry. The question that actually matters before spending money on a replacement is how much capacity has been lost, and that is not something you can judge accurately just by how the laptop feels. Both Windows and macOS can generate an exact report showing current capacity against the battery's original design capacity, and that number is what should drive the decision.

Windows: generating a battery report

1. Open Command Prompt (search "cmd" in the Start menu).
2. Type powercfg /batteryreport and press Enter.
3. The report saves as an HTML file ÔÇö the path is shown in the command output, typically in your user folder.
4. Open that file in any browser.

Look for two numbers under "Installed batteries": Design Capacity (what the battery could hold when new) and Full Charge Capacity (what it can hold now). Divide the second by the first to get your battery's current health as a percentage. The report also shows Cycle Count ÔÇö one cycle is a full charge-to-empty-to-charge sequence, and most laptop batteries are rated for 300-500 cycles before capacity drops meaningfully.

Mac: checking battery health

1. Click the Apple menu, then System Settings (or System Preferences on older macOS).
2. Go to Battery, then Battery Health.
3. macOS shows a direct status: Normal, Replace Soon, Replace Now, or Service Recommended.

For a more detailed cycle count, hold the Option key while clicking the Apple menu, choose System Information, and look under Power for Cycle Count and Full Charge Capacity.

How to read the numbers

• Above 80% capacity: Normal wear. No action needed.
• 60-80% capacity: Noticeably reduced runtime. Still usable, but replacement is worth considering if the shorter battery life is affecting how you use the laptop.
• Below 60% capacity, or a swollen battery at any percentage: Replace it. A swollen battery in particular is a safety issue, not just a performance one ÔÇö stop using the laptop until it is addressed.

What determines how fast a battery wears out

Keeping a laptop permanently plugged in at 100% and routinely draining it to 0% both accelerate wear compared to staying roughly between 20% and 80%. Heat also matters ÔÇö a laptop that runs hot (see our overheating guide) ages its battery faster regardless of how it is charged. None of this means you need to obsessively manage charging, but it explains why two laptops of the same age and model can have very different battery health.