Compress Excel File: Fixes for Sluggish or Oversized Spreadsheets

Additional Things You Can Do

If your Excel file still feels too heavy after doing all the above, it’s time to explore more advanced options. These methods require a bit more technical knowledge but can significantly reduce file size and improve performance.

Manual ZIP archive manipulation for XLSX files

Excel files with a .xlsx extension are essentially ZIP-compressed folders containing multiple components like styles, sheets, media, and XML files. By manually accessing these contents, you can remove unnecessary elements that may be bloating the file.

Step 1: Show file extensions (if not already visible)

By default, Windows hides file extensions. You’ll need to make them visible:

1. Open File Explorer.

2. Go to the View tab at the top.

3. Click on Show, then check File name extensions.

4. You should now see .xlsx at the end of Excel files.

Step 2: Rename the file

1. Right-click on the Excel file you want to compress.

2. Click Rename.

3. Change the extension from .xlsx to .zip Example: Sales_Report.xlsx → Sales_Report.zip

4. Press Enter and confirm the warning prompt if it appears.

Step 3: Open the ZIP file

1. Right-click the newly renamed .zip file.

2. Select Open with and choose a tool like WinRAR or 7-Zip.

3. Navigate to the xl folder inside the archive.

In this folder, you can:

• Delete unnecessary embedded images.

• Clean up excess styles from styles.xml.

• Remove extra sheets from the worksheets/ folder if they are no longer needed.

Note: Always make a backup copy of your Excel file before making changes inside the ZIP structure. Editing the wrong file can break your workbook.

Step 4: Repackage the file

1. After making your changes, re-zip the contents (select everything inside, not the folder itself).

2. Rename the new ZIP file back to .xlsx Example: Sales_Report.zip → Sales_Report.xlsx

3. Open the file in Excel to ensure everything works correctly.

Important: If done incorrectly, this may corrupt the file. Always test and keep a backup.

Data segmentation and Power Query connections

Large workbooks often combine multiple data sources or serve multiple departments. Instead of maintaining one huge file, you can split the workbook into smaller, purpose-specific files and reconnect them using Power Query.

1. Create separate Excel files based on logical divisions (e.g., Sales Data, Marketing Reports, Inventory Logs).
2. In your main workbook, go to the Data tab → Get Data → From Workbook to connect to the others using Power Query.
3. Use Refresh All to keep the main workbook updated.

External image management strategies

Images, especially high-resolution ones, can drastically increase workbook size. We worked with images earlier, but here's another method. Instead of embedding these images:

• Upload them to a cloud platform (OneDrive, Google Drive, SharePoint).
• In Excel, go to Insert → Picture → From Online Pictures and link to the image's URL or cloud location.

Images can be updated externally without touching the workbook. Plus, this reduces the chance of file corruption from embedded objects.

Conclusion

A bloated Excel file can slow you down, but it doesn’t have to. Applying these file compression strategies, from compressing images to clearing Pivot caches, can significantly reduce your Excel file size.

If you're new to Excel or want to sharpen your skills further, check out our Data Manipulation in Excel, Advanced Excel Functions, and our Data Preparation in Excel courses. I also mentioned Power Query. If you are interested in trying something new, enroll in our Introduction to Power Query in Excel course also.