What makes an Excel file large?
Spreadsheets grow heavy for two main reasons. The first is pictures: logos in every sheet, product photos in a catalogue, screenshots pasted next to the data. Excel stores each one at its original size, even when it is shown as a small icon in a cell.
The second is the data itself: thousands of rows, many sheets, repeated text and formatting. That data is already stored in a compressed way, but not always with the strongest compression available.
Plume helps with both, with an important difference: pictures can usually be made much lighter, while the gain on pure data is more modest.
How Plume reduces the size of an .xlsx file
An .xlsx file is a ZIP archive. Inside, each sheet is a text file, and pictures sit in a separate media folder. Plume opens the archive in your browser and:
- recompresses the pictures with the preset you pick: High quality, Balanced or Smallest;
- repacks the whole archive with maximum compression, which also shrinks the sheets a little.
Plume never touches the content of your cells. Values, formulas, formatting, charts, filters and sheet names stay exactly the same.
What to expect: a workbook full of pictures can shrink a lot. A workbook made only of numbers and text will gain a little, since Excel already compresses that data. Plume shows you the size before and after, so you know right away.
Your spreadsheet stays fully editable
The file you download is a normal .xlsx workbook. You can open and edit it in:
- Microsoft Excel (Windows, Mac, web and mobile);
- Google Sheets;
- LibreOffice Calc;
- Numbers on Mac and iPhone.
Your formulas keep calculating and your charts keep updating. Only the modern .xlsx format is supported. Older .xls files must first be saved as .xlsx. Macro-enabled workbooks (.xlsm) and binary workbooks (.xlsb) are not covered by this tool.
Tips to make an Excel file even smaller
Compression does the heavy lifting on pictures. If your workbook is still large, these classic tips, done in Excel, can help:
- Delete empty rows and columns that still carry formatting. Excel sometimes thinks a sheet goes down to row one million.
- Remove sheets you no longer need, such as old copies or test tabs.
- Replace formulas by values in archived data that will not change.
- Clear unused pivot table caches and old named ranges.
Then run the file through Plume to compress the pictures and repack the archive.
Share spreadsheets by e-mail, privately
Budgets, payroll, client lists, price lists: spreadsheets often contain the most confidential data in a company. Unlike most online tools that upload your files, Plume works entirely in your browser. Your workbook never leaves your device, and the tool keeps working offline once loaded.
A lighter file is easier to send: under the 20 MB Outlook and 25 MB Gmail limits, it goes through as a normal attachment. It also opens and syncs faster on shared drives.
Free, with no account, no watermark and no daily limit. Compress several workbooks at once and download a ZIP. Working on documents and slides too? Try Compress Word and Compress PowerPoint.
When does compressing an Excel file help the most?
Some workbooks benefit much more than others. Compression is most useful for:
- Product catalogues and price lists with a photo on each row.
- Reports and dashboards with logos, screenshots or pasted charts as images.
- Inventory and inspection sheets where photos taken on a phone were inserted directly.
- Templates that are copied many times, where every saved MB is multiplied.
For a large data export with no pictures, the file is already compressed by Excel, so expect a small gain. In that case, the tips above, such as removing empty formatted rows, often do more.