How to Check Laptop Battery Health on Windows, Mac and Chromebook
How to check laptop battery health on Windows (powercfg battery report), Mac and Chromebook, read design vs full charge capacity, and know when to replace it.
Published · Updated by Ali Blogger
Quick answer: on Windows, open Command Prompt or PowerShell, run powercfg /batteryreport, and compare Design Capacity with Full Charge Capacity in the report. On a Mac, open System Settings > Battery and click the info button next to Battery Health to see Maximum Capacity. On a Chromebook, open the Diagnostics app. On any laptop, our free Battery Health Test runs in the browser in seconds.
Battery health is the single most important spec on any laptop more than 12 months old, and the most commonly misunderstood. Below is how to check it on every system, what the numbers mean, and what counts as a healthy or worn-out battery.
The three numbers that matter
Every modern laptop battery reports three values to the operating system:
- Design Capacity: the energy the cell could store when brand new, in mWh (milliwatt-hours) on Windows or in cycles + max capacity on macOS. This number never changes.
- Full Charge Capacity: the energy the cell can store today after losing some capacity to ageing. This decreases over time.
- Cycle Count: how many times the battery has been discharged and recharged the equivalent of one full battery's worth.
Battery health is simply Full Charge Capacity ÷ Design Capacity, and wear is the rest. A laptop with a 60,000 mWh design capacity and 48,000 mWh full charge capacity has 80% health, or 20% wear.
How to check battery health on Windows 10 and 11
Windows has a detailed battery report built in. You don't need to install anything.
- Right-click the Start button and open Terminal, PowerShell or Command Prompt.
- Type
powercfg /batteryreportand press Enter. - Windows prints where it saved the report, usually
C:\Users\YourName\battery-report.html. Open that file in your browser. - In the Installed batteries section, read DESIGN CAPACITY, FULL CHARGE CAPACITY and CYCLE COUNT.
- Divide full charge capacity by design capacity to get your battery health percentage.
Two more sections of the report are worth a look. Battery capacity history shows how full charge capacity has dropped week by week, so you can see whether wear is steady or suddenly speeding up. Battery life estimates compares how long the laptop runs now with how long it ran at design capacity.
Some laptops leave the cycle count blank. That is a firmware limitation, not a fault, and the capacity numbers are still accurate.
Manufacturer battery tools
Most laptop makers also show battery health in their own support app: Lenovo Vantage, Dell SupportAssist or Dell Power Manager, HP Support Assistant and MyASUS all include a battery status page. HP and Dell laptops can also run a battery check from the startup diagnostics, which works even when Windows will not start.
How to check battery health on a Mac
- Open System Settings > Battery.
- Next to Battery Health, click the info button. macOS shows the status (Normal or Service Recommended) and, on recent versions, 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. Read Cycle Count and Condition.
Apple rates most recent MacBook batteries to keep 80% of their capacity at 1,000 cycles.
How to check battery health on a Chromebook
Open the launcher, search for Diagnostics and open the app. The battery section shows battery health and cycle count. On older ChromeOS versions without the Diagnostics app, press Ctrl + Alt + T to open crosh and run battery_test.
How to check battery health on Linux
Run upower -i /org/freedesktop/UPower/devices/battery_BAT0 in a terminal (the battery may be named BAT1 on some laptops). Compare energy-full with energy-full-design. Recent versions also print the health directly as capacity.
Check battery health online in your browser
Open our Battery Health Test. It works on any laptop with a modern browser and will:
- Show your current charge level and charging state.
- Estimate your discharge rate (% per hour) under your current workload.
- Calculate an approximate health score from runtime behaviour.
- Let you run a 5-minute stress test to compare discharge under load.
Browsers do not expose design capacity, so for an exact health percentage combine the browser test with the Windows battery report or the Mac and Chromebook steps above.
What counts as good, average, or bad
| Wear % | Cycle count | Verdict |
|---|---|---|
| 0–10% | < 100 | Like new |
| 10–20% | 100–400 | Healthy, normal use |
| 20–30% | 400–700 | Mild degradation, still serviceable |
| 30–50% | 700–1000 | Worn; replacement recommended within 6–12 months |
| 50%+ | 1000+ | End of useful life |
Apple defines a battery as "consumable" once it's below 80% of original capacity after the rated cycle count (1000 on most recent Macs). Most Windows OEMs publish similar thresholds.
Signs your laptop battery needs replacing
- Health below about 70% and runtime too short for your day.
- The laptop shuts down suddenly at 20% or 30% instead of running to empty.
- The battery percentage jumps, for example from 40% to 10% in a few minutes.
- Windows warns "Consider replacing your battery", or macOS shows Service Recommended.
- Swelling: a lifted touchpad, a bottom panel that no longer sits flat, or a gap opening in the case. Stop using the laptop on battery, don't charge it unattended, and have the battery replaced promptly. A swollen lithium-ion battery is a safety risk.
Why batteries wear out
Lithium-ion cells lose capacity for three main reasons:
- Calendar ageing: even unused, cells lose 2–4% per year as the electrolyte degrades. A laptop sitting in a warehouse for two years already has measurable wear.
- Cycle ageing: every full discharge cycle consumes a tiny amount of active lithium.
- Stress ageing: long periods at 100% charge, high temperatures, or deep discharges below 5% accelerate damage dramatically.
How to extend battery life
Modern OSes already do most of the heavy lifting (smart charge limits, optimized charging), but you can help:
- Keep state of charge between 20% and 80% when possible. Avoid leaving the laptop plugged in at 100% for days.
- Enable "Optimized Battery Charging" (macOS) or "Smart Charging" (Windows OEM tools like Lenovo Vantage, Dell Power Manager, ASUS Battery Health Charging).
- Avoid heat. The biggest killer is leaving the laptop on a soft surface that blocks vents, or in a hot car.
- Update firmware. Battery firmware updates re-calibrate capacity reporting and sometimes fix charging-curve bugs.
- Re-calibrate every few months: fully charge, then discharge to 5%, then charge to 100%. This corrects gauge drift, not actual capacity.
Replacing a worn battery
If wear is above 30% and the laptop is older than 3 years, replacement is usually cost-effective:
- MacBooks: official Apple battery replacement is $129–$249 depending on model, takes 3–5 days.
- Most Windows laptops: third-party batteries cost $40–$120. Self-replacement is straightforward on machines with an accessible bottom panel; ultrabooks may require professional service.
- Always buy from reputable suppliers (iFixit, OWC, official OEM). Cheap no-name cells often misreport capacity to look new while delivering far less runtime.
Common questions
How do I check my laptop battery health?
On Windows, run powercfg /batteryreport and compare Design Capacity with Full Charge Capacity in the report. On a Mac, open System Settings > Battery and click the info button next to Battery Health. On a Chromebook, use the Diagnostics app. For a quick check in any browser, use our Battery Health Test.
What is a good battery health percentage for a laptop?
Above 80% is healthy. Between 60% and 80% the battery still works but runtime is noticeably shorter. Below 60%, most people will want a replacement.
How many charge cycles does a laptop battery last?
Most laptop batteries are rated for 300 to 1,000 full cycles before they fall to about 80% of their original capacity. Recent MacBooks are rated for 1,000 cycles.
Can I check battery health without installing software?
Yes. Windows has the built-in powercfg /batteryreport command, macOS shows battery health in System Settings, ChromeOS has the Diagnostics app, and our Battery Health Test runs in your browser.
Does keeping my laptop plugged in damage the battery?
Sitting at 100% charge for long periods, especially when the laptop runs warm, speeds up wear. If your laptop maker offers a charge limit (often 80%) in its support app, turn it on when the laptop mostly stays on a desk.