Checking disk space usually means answering one question: is there room for what you’re about to install or update? Read two numbers for each drive, free space and total capacity, in File Explorer under This PC, then compare the free figure with what the installer or update asks for. If C: comes up short, Settings > System > Storage shows which kinds of files are taking the room.
Is there enough room? Compare the right numbers
Capacity is the size of the drive or partition. Free space is what is left. Most decisions depend on free space on one specific drive, usually C:, where Windows and most programs live. Use this table to decide which number matters:
| What you’re about to do | Number to check | Compare it with |
|---|---|---|
| Install a program or game | Free space on the drive it installs to | The size the installer or store page lists, plus room for updates and saves |
| Install a Windows update | Free space on C: | What Windows Update reports; if it says there isn’t enough space, free some and try again |
| Move to Windows 11 | Capacity of the system drive | Microsoft’s Windows 11 requirements: 64 GB or greater available storage, with more needed over time for updates |
| Copy a big folder to another drive | Free space on the destination drive | The folder’s size (see the folder method below) |
The methods below run from a quick glance to the most precise figures, so stop at the first one that answers your question.
The glance check: This PC in File Explorer
- Select File Explorer on the taskbar, or press Windows key + E.
- Select This PC in the left pane.
- Look under Devices and drives. Each drive shows a bar and a line such as “58.3 GB free of 237 GB”: the first number is free space, the second is capacity.
USB sticks and external drives appear in the same list once they are plugged in. The bar changes color when a drive is nearly full, which makes a crowded C: drive easy to spot.
Exact figures for a drive or one folder
This PC rounds its numbers. For precise values, right-click the drive in This PC and choose Properties. The General tab lists used space, free space and capacity in both bytes and gigabytes, with a pie chart. Use the byte figures when an installer quotes an exact requirement, or when you want to compare before and after a cleanup.
To find out whether a folder will fit on another drive, or which folder is eating space, right-click it and choose Properties. The General tab shows its size and the number of files and folders it contains; large folders take a few seconds to count. To compare files inside a folder, switch File Explorer to the Details view and sort by Size.
The folder method works best on your own folders, such as Downloads, Videos or a game library. Don’t delete anything inside the Windows or Program Files folders to make room; use Windows’ own cleanup tools instead.
Scripted: PowerShell and Command Prompt
A command gives every volume’s numbers at once, which is handy for copying into a support request or checking a PC remotely.
- PowerShell: run
Get-Volume. Each row shows the DriveLetter, FileSystemLabel, FileSystem, HealthStatus, SizeRemaining (free space) and Size (capacity). For one drive, useGet-Volume -DriveLetter C. Microsoft’s Get-Volume reference lists every property. - Command Prompt: run
fsutil volume diskfree c:to report free and total space for C:. Change the letter for other drives. If you get an access error, open Command Prompt as administrator and run it again.
Find out what is filling the drive
Once you know C: is short on space, open Settings > System > Storage. Microsoft’s Storage settings guide describes the page, which groups usage into categories such as apps, temporary files and system files, and offers Storage Sense. Storage Sense can automatically free up space by deleting items like temporary files and Recycle Bin contents.
For a drive other than C:, look further down the same page for the link to storage used on other drives (in Windows 10 it is labeled View storage usage on other drives). Storage shows categories, not individual files; to find the biggest files, use the Details view sorted by Size, as described above.
The category breakdown and cleanup choices are covered in detail in checking storage on Windows 10 and freeing up space. For the quickest win, clearing temp files in Windows 10 often recovers several gigabytes. If cleanup isn’t enough, increasing C drive space covers the bigger options.
Why the numbers can mislead
- Some space never appears in This PC. Recovery partitions, partitions without a drive letter, and unallocated space on a new or resized disk don’t appear in This PC. Right-click Start and choose Disk Management to see every disk and partition with its capacity and free space. Disk Management can show the EFI System and Recovery partitions as 100 percent free even though they hold files Windows needs, so leave them alone. Use it to look, not to experiment: deleting or formatting a partition here erases its data. If you are adding a second drive, this is also where it appears before it gets a letter. To confirm the physical size and type of the drive, see checking SSD size in Windows 10.
- Windows counts gigabytes differently from drive makers. A drive sold as 256 GB shows a smaller capacity in Windows, because Windows measures in binary units and recovery partitions take a share.
- Hidden system files take space. The hibernation file and the page file live on C: and don’t show in your folders.
- A previous Windows installation can sit on the drive after an upgrade. Microsoft warns that removing it means you can no longer go back to the earlier version, so decide before you delete it.
A note on Windows 10 support
These steps work on any Windows 10 PC. Microsoft ended Windows 10 support on October 14, 2025, and its end of support page says consumer Extended Security Updates can protect a PC until October 12, 2027. If you are checking space because you plan to move to Windows 11, the capacity row in the table at the top is the one to watch.
Disk space questions
How do I check the space on a USB stick or external drive?
Plug it in and open This PC; it appears under Devices and drives with its own bar. Right-click it and choose Properties for exact figures, or run Get-Volume with its drive letter.
Do these steps work in Windows 11?
Yes. This PC, drive Properties, the commands and Settings > System > Storage all work the same way. Windows 11 also adds Cleanup recommendations under Storage.
Does deleting files free up space right away?
Not until the Recycle Bin is emptied. Microsoft notes you need to empty the Recycle Bin to remove deleted files from the device completely, so check This PC again after emptying it.
Once you have the two numbers for the drive that matters, compare them with the table at the top and either go ahead or free up space first.
Kermit Matthews runs Live2Tech from just outside Philadelphia. He is an IT specialist with over 20 years of experience, from a university help desk to small-business IT, IT management and his own consulting practice, and has written tech guides full time since 2020. Steps are checked against the current software on a real device or the maker’s official documentation. More about Kermit.