Compress Excel Files Online — Reduce XLSX Size
Shrink XLSX, XLS and XLSB workbooks in your browser and download a smaller file that still opens in Excel. Unused styles, images, charts and macros are stripped; cell values and formulas stay unless you choose values only. The file never leaves this device.
Online Excel Compressor
Your workbook is rewritten locally in this browser tab. It is not uploaded to Kanaries or any other server.
- 01Accepts .xlsx, .xlsm, .xls, .xlsb and .ods files up to 25 MB.
- 02Downloads a smaller Excel file, not a .zip or .gz that Excel cannot open.
- 03Keeps cell values and formulas; drops images, charts, macros and most formatting.
- 04Optional XLSB output for another size cut, and a values-only mode if formulas can go.
- 05No Excel, no signup, no upload — works on phones and tablets too.
An Excel Compressor Built for Oversized Workbooks
Still an Excel File
The result is a regular .xlsx or .xlsb workbook. Open it in Microsoft Excel, Google Sheets, LibreOffice or Numbers without unzipping anything.
Rewrite, Then Compress
The tool rebuilds the workbook from cell data and writes it with ZIP compression. That removes the unused styles, drawing parts and cache files that usually inflate exports.
XLS to XLSX in One Step
Legacy .xls files are often several times larger than they need to be. Saving them as compressed .xlsx is one of the largest size wins this page offers.
XLSB When You Need It Smaller
Excel Binary Workbook (.xlsb) stores the same sheets in a tighter binary container. Choose it when the .xlsx is still too big to email.
Private by Design
Parsing and writing run in a background worker inside your browser. Finance, HR and customer workbooks stay on your device.
Honest About What Is Dropped
Charts, images, macros, pivot caches and most cell formatting are not preserved. If you need those, keep the original file and compress a copy.
Why Excel Files Get So Large
An Excel workbook is a ZIP package of XML, binary caches, media and style tables. A 2 MB table of numbers can become a 20 MB file after a few rounds of copy-paste, conditional formatting, embedded logos and unused defined names.
Use the compressor when you need a smaller file that still opens as a spreadsheet. Keep the original if you must preserve charts, images, macros or pixel-perfect formatting.
- Images and Charts
- A single high-resolution logo or a sheet of charts is often larger than the data itself. This compressor drops media and drawings, which is why exported reports shrink the most.
- Unused Styles and Caches
- Excel keeps style records, printer settings and calculation caches even after you delete the cells that used them. Rewriting the file from values clears that leftover XML.
- Old .xls Workbooks
- The binary .xls format from Excel 97–2003 does not compress like modern .xlsx. Converting those files is the usual fix when an attachment will not go through email.
- Gzip Is the Wrong Tool
- An .xlsx is already a ZIP archive. Wrapping it in .gz or another .zip rarely helps and Excel cannot open the result. This page writes a smaller workbook instead.
How to Compress an Excel File Online
- 01
Choose the Workbook
Click the upload area or drag an .xlsx, .xls, .xlsb or .ods file into it. Try the sample workbook if you want to see the size change first.
- 02
Pick the Output
XLSX is the default and opens everywhere. Switch to XLSB for a smaller binary workbook. Tick values only if formulas can be replaced with the numbers Excel already calculated.
- 03
Check the New Size
The tool shows the original size, the compressed size and the percentage saved. Files that are already compact are labelled instead of pretending they shrank.
- 04
Download the Smaller File
Save the rewritten workbook and open it in Excel to confirm the sheets you need. Keep a copy of the original if you still need charts or images.
When an Excel Compressor Is the Right Tool
Email Attachments That Bounce
Outlook and many mail servers reject files above 20–25 MB. A rewritten .xlsx or .xlsb is the usual way to get a report through.
System Exports Full of Formatting
CRM, ERP and accounting exports often ship with unused styles and empty used-ranges. Rewriting them from cell values cuts that bloat.
Old .xls Files on Shared Drives
Convert a folder of Excel 97–2003 workbooks to compressed .xlsx when you need them smaller and still editable.
Sending Data, Not Decoration
If the recipient only needs the numbers, dropping images and charts is the fastest size cut, and it is safer than mailing macros.
Phones and Slow Uploads
A smaller workbook is easier to open on a phone and cheaper to upload to Drive, Dropbox or an S3 bucket.
Excel Compressor FAQ
Q01How do I compress an Excel file online?
Drop an .xlsx, .xls or .xlsb file into the tool above. It is rewritten in your browser into a smaller workbook you can download. No Microsoft account or installation is needed.
Q02How can I reduce Excel file size without zipping it?
This compressor writes a new .xlsx or .xlsb from the cell data. Excel opens that file directly. Wrapping the original workbook in ZIP or GZ usually does not help, because .xlsx is already compressed.
Q03Why is my Excel file so large?
Images, charts, unused styles, printer settings, pivot caches and leftover formatting are the usual causes. A sheet of numbers is rarely the bulk of the file.
Q04Does compression keep formulas?
Yes, by default. Tick values only if you want to replace formulas with the last calculated values, which can make the file smaller still.
Q05Is my Excel file uploaded to a server?
No. The workbook is read and rewritten entirely inside your browser. Closing the tab removes it from memory.
Q06Will Excel still open the compressed file?
Yes. The download is a standard .xlsx or .xlsb workbook. Charts, images, macros and most formatting will be missing, so open it once to check.
Q07How large can the file be?
Files up to 25 MB are supported. A single worksheet can have up to 200,000 rows, 2,000 columns or 2 million cells; larger sheets are rejected instead of freezing the tab.
Q08Can I compress a password-protected workbook?
No. Encrypted files cannot be parsed in the browser. Remove the password in Excel, compress the copy, then protect the result if you still need to.