To compress a Windows 11 drive in File Explorer, the drive must use NTFS. Right-click it in This PC, open Properties, and turn on the compression option. NTFS compression is lossless and transparent to apps: they receive the ordinary file contents without a separate extraction step, though compression uses CPU resources and can slow large sequential reads. Microsoft documents how NTFS compression works.

What NTFS compression changes

NTFS uses Lempel-Ziv compression, which reduces redundant data without losing file contents. The amount of space recovered depends on the files being compressed, so there is no fixed saving to expect. Microsoft’s NTFS technical guidance also cautions that large sequential reads are relatively slower because Windows must decompress multiple compression units. It advises against compressing large files or files that are critical to system performance.

One result gives a sense of what a particular drive might yield, not a forecast for yours. João Carrasqueira reported on XDA Developers that compressing a drive with 333 GB of data in use recovered 68 GB. Windows estimated more than nine hours; the operation took around two hours. Carrasqueira also reported no noticeable slowdown on his laptop.

Compress an NTFS drive in File Explorer

The drive-level option applies to an NTFS drive. XDA describes this route:

  1. Open File Explorer, then select This PC.
  2. Right-click the drive you want to compress and choose Properties.
  3. Turn on the drive-compression option and apply the change.

The time and space saved depend on the drive’s contents. After the operation finishes, check the free-space figure in This PC to see the result.

Compress selected folders or files

ZacsTech’s English-language tutorial covers NTFS compression on drives, folders, and files.

To target specific items instead, use their Properties:

  1. In File Explorer, right-click a folder or file and choose Properties.
  2. Open Advanced and select the compression attribute.
  3. Choose whether the setting should apply to subfolders, then apply it.

A folder’s compression attribute sets the default for new files and subfolders. Changing that attribute alone does not necessarily compress files already inside the folder, as Microsoft’s documentation on compression attributes explains.

NTFS compression, Compact OS, and ZIP

These options serve different purposes. NTFS compression keeps files accessible to applications in their ordinary form; ZIP uses an archive workflow. Compact OS instead runs Windows from compressed operating-system files. Microsoft provides separate Compact OS controls through Compact.exe, including /CompactOS:Query, /CompactOS:always, and /CompactOS:never.

MethodWhat it compressesHow you access or control itPractical difference
NTFS compressionFiles on an NTFS drive, folder, or fileFile Explorer Properties or the compact commandApps receive uncompressed file contents; compression uses CPU resources and large sequential reads are relatively slower.
Compact OSWindows operating-system filesCompact.exe with a Compact OS optionChanges how the operating system is stored and run; it is separate from compressing a data drive. Microsoft’s Compact OS documentation
ZIPFiles collected in an archiveWindows’ compressed-folder optionYou access the contents through the archive or extraction workflow. XDA Developers describes the distinction.