Reduce Excel File Size
Upload a large Excel file and reduce its size instantly. Choose between compress-only (preserves all formatting) or strip-formatting (maximum reduction). Your file never leaves your browser.
Drop your Excel file here
or click to browse — .xlsx, .xls, .xlsm, .xlsb
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Why Excel Files Get Large
Excel files can grow unexpectedly large for several reasons — most of which have nothing to do with the actual amount of data:
- Formatting applied to entire columns: Selecting a whole column and applying a colour or font creates formatting entries for over a million cells, even if only 100 have data
- Conditional formatting on large ranges: Complex conditional formatting rules across large ranges add significant overhead
- Hidden sheets with large data: Sheets you cannot see can still contain thousands of rows
- Embedded images: Charts and images are stored uncompressed inside the xlsx container
- Poor default compression: Some versions of Excel save xlsx files with minimal compression — re-saving with maximum compression can reduce size by 30–50% with no other changes
Frequently Asked Questions
How much can it reduce my file size?
It depends on how the original file was saved. Files saved by Excel with default settings typically compress 20–50% with the compress-only option. Files with heavy formatting (many colours, conditional formatting, custom fonts) can reduce 40–80% with the strip-formatting option.
Will my data be changed?
No data is changed. The compress-only mode re-saves the exact same workbook with better ZIP compression. The strip-formatting mode removes visual formatting (colours, fonts, borders) but keeps every value, formula, and sheet.
Are my files uploaded to a server?
No. Everything runs in your browser using JavaScript. Your file never leaves your device.
Why is my Excel file so large?
Common causes: excessive formatting applied across entire columns/rows, hidden sheets with large data, conditional formatting on large ranges, embedded images, and many named ranges or defined names. The strip-formatting mode addresses the first cause directly.
Will formulas still work after reducing?
In compress-only mode, yes — nothing is changed except the compression level. In strip-formatting mode, all values and formula text are preserved, but any conditional formatting rules are removed.