Disk Space Cleanup Guidance: Using NTFS Compression
Many folks are familiar with the concept of zipping files or folders in order to reduce their size. However, Windows has the built-in ability to compress folders and files in a manner that is virtually invisible to users, offering significant space savings without changing how you work.
Quick Summary: NTFS compression is a free built-in Windows feature that automatically compresses and decompresses files behind the scenes, saving disk space without requiring you to manually zip/unzip files.
Why NTFS Compression?
The biggest advantage of using NTFS compression is its complete transparency to users. There’s no need to compress and decompress manually like with stand-alone utilities such as WinZip. Once applied, NTFS compression and decompression occurs automatically in the background, without any user intervention.
NTFS compression is also remarkably flexible in how you can apply it:
- Individual files – Compress just specific large documents
- Folders – Apply to entire directories of compatible files
- Entire drives – Maximize space savings across a complete volume
💡 Pro Tip: As its name implies, NTFS compression works only on NTFS-formatted drives (not with FAT32 or exFAT). To check your drive format, right-click any drive in File Explorer, select Properties, and look for “File system” on the General tab.
When to Use NTFS Compression
Some file types compress much better than others. For maximum space savings, focus on these highly compressible file types:
Best Compression Candidates:
- Office documents (.docx, .xlsx, .pptx)
- Text files (logs, .txt, .xml, .json, .csv)
- Uncompressed images (.bmp, .tiff)
- Database files (.mdb, .accdb)
- Email archives (.pst, .ost)
These typically compress by 30-60%
Poor Compression Candidates:
- Already compressed images (.jpg, .png, .gif)
- Video files (.mp4, .mov, .avi)
- Audio files (.mp3, .aac, .wav)
- ZIP archives (.zip, .rar, .7z)
- Installers (.exe, .msi)
These typically compress less than 5%
Performance Considerations
NTFS compression does involve some performance tradeoffs. Windows automatically decompresses files when you open them and recompresses them when closed. This process consumes CPU resources, which can impact performance when working with frequently accessed files.
For optimal results, apply NTFS compression to:
- Folders containing infrequently accessed documents
- Archive folders with reference materials
- Old project files you need to keep but rarely open
Avoid compressing:
- System files and program folders
- Files you access multiple times daily
- Files that already have poor compression ratios
How to Apply NTFS Compression
Compressing an Entire Drive
You must be logged on as an administrator or a member of the Administrators group to complete this procedure:
- Open File Explorer (or My Computer in older Windows versions)
- Right-click the drive you want to compress, and then click Properties
- On the General tab, check the Compress this drive to save disk space option
- Click Apply, then OK
- In Confirm Attribute Changes, select whether to apply to subfolders and files
Note: Compressing an entire drive can take significant time depending on its size.
Compressing Individual Files or Folders
- Open File Explorer (or My Computer in older Windows versions)
- Navigate to the file or folder you want to compress
- Right-click the item and select Properties
- On the General tab, click Advanced
- Check Compress contents to save disk space
- Click OK twice
- If compressing a folder, choose whether to apply changes to subfolders and files
Maximizing Your Results with FolderSizes
A key component of using any compression mechanism effectively is understanding how your disk space is currently being allocated. FolderSizes helps you:
- Identify exactly which files and folders are consuming the most space
- Find the best compression candidates based on file type and size
- Discover duplicate files that could be deleted instead of compressed
- Analyze compression ratios to see how much space you’ve saved
- Monitor disk space usage over time to prevent future storage issues
Take Control of Your Disk Space Today
Combine NTFS compression with powerful disk analysis for maximum storage efficiency.