1. Check whether the battery itself is worn
A worn battery drains "fast" because there's less in it to start with. Run the Windows battery report and look at full charge capacity against design capacity.
If the battery is under about 60% of its design capacity, wear explains most of the problem, and the fix is a new battery. If it's still near its design capacity, keep going: something is using the power.
2. See which apps used the battery
Windows 11 tracks battery use by app. Go to Settings > System > Power & battery and expand Battery usage. Under Battery levels, choose Last 24 hours, then select an hour where the level dropped fast to see which apps were responsible.
Browsers with many tabs, video calls, games and sync tools are the usual suspects. Close what you aren't using.
3. Stop apps from starting on their own
Open Task Manager (Ctrl+Shift+Esc), go to the Startup apps tab, right-click anything you don't need running all the time, and select Disable. It doesn't uninstall anything. The app just won't launch at sign-in.
4. Change the power settings
- Power mode: In Settings > System > Power & battery > Power Mode, choose Best Power Efficiency to limit background activity.
- Energy saver: In Settings > System > Power & battery > Energy saver, check when it switches on, and turn on Lower screen brightness when using energy saver.
- Screen and sleep: Shorter times in Settings > System > Power & battery > Screen, sleep & hibernate timeouts cut idle drain.
- Refresh rate: On laptops with fast screens, turn on dynamic refresh rate in Settings > System > Display > Advanced display.
- Radios: Turn off Wi-Fi and Bluetooth from Quick Settings when you don't need them.
Windows also collects its own suggestions under Settings > System > Power & battery > Energy recommendations.
5. If it drains while the lid is closed
A laptop that loses a big chunk of charge overnight is usually waking up or never fully sleeping. On laptops that use modern standby, Windows can report on sleep from the last three days:
The report breaks down each sleep session so you can see which ones drained the battery and what was active. The Recent usage section of the battery report is also worth a look for the same problem.
6. Run Windows' own energy check
For a broader scan, run this with no programs or documents open:
It watches the laptop for a short time, then writes an HTML report of common energy-efficiency and battery-life problems it found. If Windows says access is denied, open the window as administrator.
Check your laptop maker's support site for firmware and driver updates, since power management bugs often get fixed there. If nothing helps and the battery tests as worn, see when to replace a laptop battery.