What "Check" means depends on what you're looking at

The phrase "how do I check" covers dozens of different tasks on phones, computers, and tablets. The most common ones are checking how much storage space you have left, seeing your battery health, finding out what operating system version you're running, and looking at what apps are using the most power or data. Each one takes a different path depending on whether you use Windows, Mac, iPhone, or Android.

This guide walks you through the most frequent checks people need to do. If you're looking for something specific — like checking your WiFi password or seeing what's connected to your network — the section headings below will help you find it quickly.

Key Takeaways

  • Storage space is found in Settings on every device type, and the path changes slightly between Windows, Mac, iPhone, and Android.
  • Battery health on iPhones is in Settings > Battery > Battery Health & Charging, while Android phones show battery information in Settings > Battery or Device Care depending on the manufacturer.
  • Your operating system version appears in Settings on all devices, and checking it takes less than a minute.
  • Apps using the most power or data are visible in the same Settings area where you find battery health, letting you see what's draining your device.
  • Restarting your device after checking these things often fixes slow performance or battery drain without needing to change any settings.

Checking storage space on Windows

On Windows 11, open Settings by pressing the Windows key and typing "Settings", then click the app that appears. Go to System in the left menu, then select Storage. The top of the page shows your total storage and how much is in use. Below that, you'll see a breakdown by category — apps, documents, pictures, videos, and other files — so you can see what's taking up the most room.

If you want to see what's inside a specific folder, right-click the folder, select Properties, and Windows will calculate the total size. This takes a few seconds for large folders. You can also use the built-in Disk Cleanup tool by typing "Disk Cleanup" in the Windows search box, which suggests files you can safely delete.

Checking storage space on Mac

Click the Apple menu in the top-left corner and select About This Mac. Click the Storage tab to see how much space you have left and what's using it. The colored bar shows your breakdown: apps, photos, backups, and other data. Click Manage to see recommendations for freeing up space, like deleting old files or moving photos to iCloud.

If you want more detail about what's in a specific folder, open Finder, right-click the folder, and select Get Info. The window that opens shows the folder's total size. For a visual breakdown of your entire drive, you can download a free app like Disk Diag or DiskSight, which shows you exactly which folders are largest.

Checking storage space on iPhone and Android

On iPhone, go to Settings > General > iPhone Storage. You'll see your total capacity and how much is used, plus a list of apps ranked by size. Tap any app to see its size and how much data it's storing. On Android, the path varies by manufacturer, but usually it's Settings > Storage or Settings > Device Care > Storage. Some phones like Samsung show the breakdown by category (apps, photos, videos, other).

Both phones let you delete apps directly from this screen. On iPhone, tap an app and select Offload App to remove it while keeping its data, or Delete App to remove it completely. On Android, tap an app and select Uninstall. You can also clear cached data — temporary files apps create — which often frees up several gigabytes without deleting anything you need.

Checking battery health on iPhone

Go to Settings > Battery > Battery Health & Charging. You'll see your maximum capacity as a percentage — for example, 85% means your battery can hold 85% of the charge it could when new. Apple considers a battery degraded when it drops below 80%. Below that, you'll see the charging optimization setting, which slows charging to 80% overnight to extend battery lifespan.

If your maximum capacity is below 80% and your phone is still under warranty or AppleCare coverage, you can get a battery replacement. If it's out of warranty, Apple charges a flat fee (usually around $70) for a replacement. You can also see which apps used the most battery in the last 24 hours or 10 days by scrolling down in the Battery settings.

Checking battery health on Android

Android doesn't show battery health the same way iPhones do. Instead, go to Settings > Battery or Settings > Device Care > Battery (the exact path depends on your phone's manufacturer). You'll see which apps used the most power and how much battery you have left. Some phones like Samsung show a battery status indicator, but most don't display maximum capacity the way iPhones do.

If you want detailed battery information on Android, you can dial *#*#4636#*#* on some phones (Samsung, Google Pixel, others) to open a hidden diagnostic menu that shows battery health. Not all phones support this code. If it doesn't work on yours, third-party apps like AccuBattery can estimate your battery health, though they're less precise than Apple's built-in tool.

Checking your operating system version

On Windows, go to Settings > System > About. Look for "Windows edition" to see if you have Windows 11 or Windows 10, and "Version" to see the specific build number. On Mac, click the Apple menu and select About This Mac. The first line shows your macOS version — for example, macOS Sonoma 14.2.

On iPhone, go to Settings > General > About and look for "Software Version". On Android, go to Settings > About phone (or About device) and scroll down to find "Android version". Knowing your version matters because some apps require a minimum version to run, and older versions may not receive security updates.

Checking what's using your data

On iPhone, go to Settings > Cellular and scroll down to see which apps used the most cellular data. You can also go to Settings > WiFi to see data use on WiFi networks. Tap any app to see its total, and you can toggle it off to prevent that app from using cellular data in the future.

On Android, go to Settings > Network & Internet > Mobile network (or Data usage) to see which apps used the most data. Some phones show WiFi data separately under a different menu. You can set data warnings and limits here too — for example, telling your phone to alert you when you've used 5GB of data in a month.

Frequently Asked Questions

Why does my phone say I'm out of storage when I deleted apps?

Deleting an app doesn't always clear its cached data — temporary files it created while running. Go to Settings and look for "Clear Cache" or "Storage" to delete these files without removing the app itself. This often frees up several gigabytes. You can also restart your phone, which clears some temporary files automatically.

What does "maximum capacity" mean for battery health?

Maximum capacity is how much charge your battery can hold compared to when it was new. A battery at 85% maximum capacity can hold 85% of its original charge. This naturally decreases over time as you charge and use the battery. It doesn't mean your battery is 85% full right now — that's shown separately as your current charge level.

Can I check how much data my WiFi network is using?

Your phone can show you which apps used data on a specific WiFi network, but it can't tell you your total household WiFi use. For that, you need to check your router's admin panel or your internet provider's website. Most routers have a web address (usually printed on the back) where you can log in and see connected devices and their data use.

What should I do if my battery health is below 80%?

If your iPhone is under warranty or has AppleCare, you can get a battery replacement. If not, you can pay for a replacement out of pocket, or you can continue using the phone — a battery at 80% capacity still works fine, it just won't hold a charge as long as it did when new. Some people replace the battery; others wait until the phone feels too slow or the battery drains too fast.

Why does my storage show as full even after I delete files?

On Windows and Mac, the system reserves space for updates and temporary files. You can't use all of your storage — typically 10 to 20% is reserved. If you're very close to full, delete large files like old backups or video files. On phones, restarting often helps because it clears temporary cache files that the storage checker might not count accurately.