Find your storage space in three clicks

You can see how much storage you have left on Windows, Mac, or an external drive in under a minute. The steps differ slightly by device, but the information lives in the same place on all of them — a settings menu that shows you total space, used space, and free space. Knowing this number matters because when your drive gets too full, files save slowly, programs freeze, and backups fail.

The fastest way is to right-click the drive itself and read the bar that appears. If you want more detail — which folders are taking up the most room, or whether a specific file is actually using the space you think it is — you can open a storage report that breaks everything down by category.

Key Takeaways

  • On Windows, right-click your C: drive, select Properties, and read the pie chart to see used versus free space when ready.
  • On Mac, click the Apple menu, select About This Mac, then Storage to see a color-coded breakdown of what is using your drive.
  • For external drives, plug them in and use the same method as your main drive — Windows Properties or Mac Storage tab — to check their space.
  • If your drive is nearly full, use Storage Sense on Windows or About This Mac on Mac to see which folders or file types are taking the most room.
  • A drive should stay below 85 percent full to keep programs running smoothly and backups working reliably.

Check storage on Windows

Right-click the C: drive in File Explorer and select Properties. A window opens showing a pie chart with two colors — one for used space (usually blue) and one for free space (usually gray). The numbers appear below the chart: "Used" shows how much is taken up, and the total capacity shows how much the drive holds altogether. Subtract used from total to find your free space, or just look at the gray section of the pie.

If you want to know which folders are eating the most space, stay in that Properties window and click the Disk Usage tab at the top. This shows a list of your largest folders — Documents, Downloads, Program Files, and so on — ranked by size. Click any folder name to see what is inside it. This is the fastest way to find that old video file or installer taking up 10 gigabytes.

For a more detailed report, open Settings, go to System, then Storage. Windows shows you a breakdown by category: Apps, Documents, Pictures, Videos, and so on. Click any category to see individual files ranked by size. You can also turn on Storage Sense here, which automatically deletes temporary files and old downloads when your drive gets too full — though you can set it to ask you first before it deletes anything.

Check storage on Mac

Click the Apple menu in the top-left corner and select About This Mac. Click the Storage tab. You see a horizontal bar with colored sections — each color represents a different type of file: red for system files, blue for apps, green for photos, orange for documents, and gray for free space. The number next to each color shows how much space it uses. The total capacity appears at the far right.

If you want to see which individual apps or files are largest, click Manage in the Storage window. Mac shows you a list of apps ranked by size, with options to delete them directly. You can also see your Downloads folder, which often holds old installers and files you no longer need. Click any item to see when you last opened it — if it has been months, you can probably delete it safely.

For the most detailed view, open Finder, click Applications, then Utilities, then open Disk Utility. Select your drive on the left and click the Info button. This shows the exact number of gigabytes used and available. It is less visual than the Storage tab but more precise if you need exact figures.

Check storage on external drives

Plug the external drive into your computer using its USB cable. On Windows, it appears in File Explorer as a new drive letter — usually D: or E:. Right-click it and select Properties to see the same pie chart and numbers as your main drive. On Mac, it appears on the desktop and in Finder. Right-click it, select Get Info, and you see the capacity and used space at the bottom of the window.

External drives fill up the same way internal drives do, and they slow down just as much when they get too full. If you are using an external drive for backups, keep at least 20 percent free space on it so the backup software has room to work. If your external drive is nearly full and you cannot delete files from it, you may need a second external drive or a larger one.

Understand what the numbers mean

A drive shows three numbers: total capacity, used space, and free space. Total capacity is the maximum the drive can hold — a 1 terabyte drive holds 1,000 gigabytes. Used space is what your files, programs, and system files take up right now. Free space is what remains. If a 1 terabyte drive shows 850 gigabytes used, you have 150 gigabytes free.

The operating system itself — Windows or Mac — takes up 20 to 50 gigabytes depending on your version and how many updates you have installed. Programs you install take up space too. A single video file can be 1 to 5 gigabytes. A photo library with thousands of pictures can be 50 gigabytes or more. Understanding these sizes helps you decide what to delete when space runs low.

Aim to keep your main drive below 85 percent full. At 90 percent or higher, Windows and Mac slow down noticeably because they need free space to create temporary files while programs run. Backups also fail when the drive is too full because the backup software cannot write new data. If you are consistently above 85 percent, you need to delete files, move them to external storage, or get a larger drive.

Find and delete large files safely

Once you know your drive is full, the fastest fix is finding and deleting the largest files. On Windows, open File Explorer, right-click your C: drive, select Properties, then click Disk Usage. Sort the folders by size and click into the largest ones. Downloads folders often hold old installers — files ending in .exe or .msi that you can safely delete once you have installed the program. Temp folders hold temporary files that Windows creates and forgets about; these are always safe to delete.

On Mac, open About This Mac, click Storage, then click Manage. Look at the Documents section and Downloads section. Files in Downloads are usually safe to delete if you downloaded them more than a few months ago. In Documents, look for old project folders, video files, or disk images (.dmg files) that you no longer need. Drag them to the Trash and empty the Trash to free up space.

Before you delete anything, ask yourself: do I need this file, will I need it in the future, and do I have a backup of it? If the answer to all three is no, it is safe to delete. If you are unsure, move it to an external drive first instead of deleting it. That way you free up space on your main drive but keep the file in case you need it later.

Monitor storage over time

Check your storage space once a month, especially if you read videos, photos, or large files regularly. A drive that was 50 percent full last month might be 75 percent full this month if you have been saving a lot. Catching it early means you can delete files gradually instead of scrambling when you run out of space suddenly.

Set a reminder on your phone or calendar to check storage on the first of each month. It takes two minutes and prevents the slowdowns and backup failures that come with a full drive. If you find yourself consistently running out of space, consider moving old files to an external drive or cloud storage regularly, rather than keeping everything on your main drive.

Frequently Asked Questions

Why does my drive show less free space than I expected?

The operating system, hidden system files, and program caches take up more space than most people realize. Windows alone uses 20 to 50 gigabytes. If you have been using the computer for years, temporary files and old program leftovers add up. Check your Downloads and Temp folders first — these often hold gigabytes of files you can safely delete.

Is it safe to delete files from the Temp folder?

Yes. On Windows, the Temp folder holds temporary files that programs create while running. Once the program closes, these files are no longer needed. You can delete everything in Temp safely. On Mac, temporary files are hidden by default, but you can use a tool like CleanMyMac or manually navigate to Library/Caches to delete old cache files. Do not delete anything from System folders unless you know exactly what it is.

What happens if my drive gets completely full?

Your computer slows down dramatically, programs freeze or crash, and backups fail. Windows and Mac need free space to create temporary files while running. If you hit 100 percent full, you may not be able to save new files at all. Delete files when ready or move them to external storage. Aim to keep at least 10 to 15 percent free space at all times.

Can I check storage on my phone the same way?

Yes, but the method is different. On iPhone, go to Settings, then General, then iPhone Storage. On Android, go to Settings, then Storage. Both show you how much space is used and free, plus a breakdown by app and file type. The same rule applies — keep at least 10 to 15 percent free for the phone to run smoothly.

Should I use cloud storage instead of checking my drive?

Cloud storage like OneDrive, Google Drive, or iCloud can help, but you still need to manage your main drive. Cloud storage is best for files you do not need every day — old photos, archived documents, or backups. Keep your most-used files and programs on your main drive for speed, and move older files to cloud storage or external drives to free up space.