Where to find your storage information

Windows and Mac both show you how much storage you're using and how much space remains. On Windows, open File Explorer, right-click on "This PC" in the left sidebar, and select "Properties" — you'll see a bar graph showing used and free space for each drive. On Mac, click the Apple menu, select "About This Mac", then go to the "Storage" tab to see what's taking up room.

These built-in tools are the fastest way to get a quick answer. They show you total capacity, used space, and available space in one view. If you need more detail about what's actually consuming that space, you'll need to dig deeper — but the Properties or Storage tab is always your starting point.

Key Takeaways

  • Windows shows storage details in File Explorer under "This PC" Properties; Mac shows them in "About This Mac" under the Storage tab.
  • A storage bar that's nearly full (over 90 percent used) can slow your computer down and prevent updates from installing.
  • Windows' built-in Disk Usage tool and Mac's Storage tab both break down what types of files are consuming the most space.
  • If you can't see your full drive capacity in these tools, your drive may be partitioned, and you'll need to check Disk Management (Windows) or Disk Utility (Mac).

Understanding what the numbers mean

Your drive has a total capacity — usually measured in gigabytes (GB) or terabytes (TB). The storage bar shows how much of that capacity is currently in use. If your bar shows 850 GB used out of 1 TB total, you have about 150 GB of free space left.

Free space matters more than you might think. When your drive gets above 90 percent full, Windows and Mac both slow down noticeably because the operating system needs breathing room to write temporary files, create backups, and run updates. If you're consistently above 85 percent capacity, it's time to delete files or move them to external storage.

Finding what's taking up the most space on Windows

After you've seen the overall storage bar, you can find out which files and folders are the culprits. In Windows 10 and 11, go to Settings, then System, then Storage. Click on "Storage sense" or scroll down to see a breakdown by category — Apps & games, Documents, Pictures, Videos, and so on. Click any category to see what's inside and delete what you don't need.

For a more detailed view, use the built-in Disk Usage tool. Press the Windows key, type "Disk Usage", and open "Disk usage" from the results. This tool scans your entire drive and shows you the largest folders and files in order. It takes a few minutes to complete the scan, but you'll see exactly which folders are eating up space — often it's old downloads, temporary files, or a backup folder you forgot about.

If you want even more control, third-party tools like WinDirStat or TreeSize Free show a visual map of your drive where larger files appear as bigger blocks. These aren't necessary for basic storage management, but they're useful if you're trying to reclaim a lot of space quickly.

Finding what's taking up the most space on Mac

On Mac, the Storage tab in "About This Mac" breaks down your drive by category: Documents, Photos, Backups, Mail, Trash, and Other. Click on any category to see what's inside. Documents and Photos are usually straightforward — you can delete old files directly. Backups and Mail often surprise people; Mail can easily consume 20 GB or more if you've never cleaned it out.

The "Other" category is harder to understand because it includes system files, caches, and temporary data. If "Other" is taking up more than 20 percent of your drive, you can use the built-in Disk Utility to get more information. Open Disk Utility (in Applications > Utilities), select your drive from the left sidebar, and click "Info" — this shows you the same breakdown as "About This Mac" but with slightly more detail.

For a visual breakdown similar to Windows' Disk Usage tool, Mac users can try free tools like Disk Diag or DiskSight. These show you which folders and files are largest, making it easier to spot what to delete.

What to do if your drive is partitioned

Sometimes a single physical drive is divided into multiple partitions, each with its own letter (C:, D:, E: on Windows) or name on Mac. If you see multiple drives listed in File Explorer or Disk Utility, you may have partitions. Each partition has its own storage bar and capacity.

On Windows, if you want to see all your partitions at once, open Disk Management. Press the Windows key, type "Disk Management", and open "Create and format hard disk partitions". You'll see every partition on every drive, along with its capacity and used space. This is also where you can resize or delete partitions, though that's a more advanced task.

On Mac, open Disk Utility and select your drive from the left sidebar. The "Partitions" or "Volumes" section shows you how the drive is divided. If you have multiple partitions, each one shows its own capacity and used space.

Checking external drives and USB storage

External hard drives, USB flash drives, and SD cards all show up in File Explorer (Windows) or Finder (Mac) just like your main drive. Right-click or Control-click on the device and select Properties (Windows) or Get Info (Mac) to see its total capacity and how much space is used.

External drives fill up the same way internal drives do, and they can also slow down or fail if they get too full. The same rule applies: keep at least 10 to 15 percent of the drive empty. If you're using an external drive for backups, make sure you have enough free space on it to hold a complete copy of the files you're backing up.

When to clean up your storage

You don't need to obsess over storage, but certain situations demand attention. If Windows or Mac tells you that storage is low, act immediately — your computer won't be able to install updates or create temporary files it needs to run smoothly. If you're above 85 percent capacity, start deleting or moving files before you hit a problem.

Common things to delete safely: old downloads (check your Downloads folder), duplicate photos (especially if you've synced from multiple devices), old email attachments, and temporary files. Windows has a built-in cleanup tool called Disk Cleanup — press the Windows key, type "Disk Cleanup", and open it to remove temporary files automatically.

If you need to keep files but free up space, move them to an external drive or cloud storage like OneDrive, Google Drive, or Dropbox. This keeps the files accessible without taking up space on your main drive.

Frequently Asked Questions

Why does my drive show less total space than I paid for?

Manufacturers measure storage in decimal (1 TB = 1 trillion bytes), but computers measure it in binary (1 TB = about 1.1 trillion bytes). A 1 TB drive shows up as about 931 GB in Windows or Mac. The difference is normal and not a defect. Additionally, the operating system itself takes up 20 to 50 GB depending on your version.

What's the difference between used space and free space?

Used space is what your files, programs, and operating system currently occupy. Free space is what's left available for new files and temporary data. If you have 1 TB total and 850 GB used, you have 150 GB free. You can only store new files in the free space.

Can I trust third-party storage analysis tools?

Yes, tools like WinDirStat, TreeSize, and Disk Diag are safe and widely used. They simply scan your drive and show you what's there — they don't modify anything unless you tell them to. Stick to tools from established sources like GitHub or reputable software sites, and avoid anything that promises to "clean" your drive automatically without showing you what it's deleting.

Is it safe to delete files from the "Other" category on Mac?

Not always. "Other" includes system caches, which are safe to delete but will rebuild automatically, and system files, which you should never delete. Use the built-in Disk Cleanup or Storage Sense tools instead of manually deleting from "Other" — they know which files are safe to remove.

How often should I check my storage?

Check once a month if you download a lot of files or take many photos. If you mostly use cloud storage and streaming services, checking every few months is fine. The key is to catch problems before your drive gets above 90 percent full, which can happen quickly if you're not paying attention.