Compress ODS spreadsheets without touching your data
An ODS file, the native format of LibreOffice Calc, is a ZIP archive of XML plus any pictures you've added. The cell data is stored very efficiently: even a sheet with tens of thousands of rows is often only a few hundred kilobytes. When an ODS file is large, the cause is almost always images, like a logo saved at poster size, product photos pasted straight from a camera, or screenshots stored in a bulky format. This tool shrinks those pictures to a sensible size, removes a few extras the file doesn't need, and rebuilds a valid spreadsheet with every cell, formula, chart, and sheet exactly as it was.
Everything happens in your browser. Your spreadsheets are never uploaded.
How to use it
- Choose one or more
.odsfiles, or drag them onto the box. - Pick the largest image size and photo quality. The recommended settings suit almost any spreadsheet.
- Check each result: size savings, the verification badge, and what happened to each image.
- Download the compressed spreadsheet, or all of them at once as a ZIP.
What this compressor changes
| Part of the file | What happens | Effect on your spreadsheet |
|---|---|---|
| Large photos | Resized to the size you chose and re-saved as JPEG | Look the same at normal zoom and stay anchored to the same cells |
| Photos stored as PNG or BMP | Converted to JPEG, with every reference updated | None, except a much smaller file |
| Logos, icons, screenshots | Kept as PNG, resized only if over your limit | Edges and text stay sharp, and transparency is kept |
| Preview thumbnail | Removed | None. It's rebuilt the next time you save. |
| Saved printer setup | Removed | None. Print settings like page orientation and scaling are stored elsewhere and kept. |
| Cells, formulas, charts, sheets, styles | Untouched | Your data is never rewritten |
Phone photos taken in portrait orientation keep their rotation exactly as before. A picture is only replaced when the new version is meaningfully smaller.
Why "maximum ZIP compression" doesn't help
Some tools only re-pack an ODS archive at a higher compression level. That rarely saves more than one or two percent, because the XML inside is already compressed and photos can't be squeezed further by zipping. The real savings are in the pictures, which is where this tool focuses.
How each file is checked
After compressing, the tool reopens its output and checks it the way LibreOffice would. It confirms that the archive is valid, that every part passes its checksum, that every picture the spreadsheet refers to is present and listed in the manifest, and that every edited XML file is well-formed. Problems that were already in the original file aren't blamed on the compression. The green Verified badge means everything checks out. In testing, compressed spreadsheets opened in LibreOffice Calc with exactly the same cell values as the originals.
Frequently asked questions
Will my formulas or values change?
No. Cell content, formulas, formatting, charts, and sheets are never rewritten. Only pictures and a few non-essential extras are touched.
Are my files uploaded?
No. The spreadsheet is opened, optimized, and rebuilt inside your browser. Nothing is sent to a server.
My spreadsheet barely shrank. Why?
It probably has few or small pictures. ODS stores cell data very compactly, so a spreadsheet without images is usually already small. If it's still too big, the size usually comes from unused rows and columns with formatting applied, which you can clear in LibreOffice.
Can it compress password-protected ODS files?
No. Encrypted files can't be changed without the password. Remove the password in LibreOffice, compress, then add it back.
Does it work with Excel files?
This page is for OpenDocument spreadsheets. Excel's .xlsx and .xls formats are structured differently and need their own tool.
Will charts still work?
Yes. Charts are stored as embedded objects and are copied exactly. Only photographic images are optimized.