XLSX File Format (.xlsx)
An XLSX file is a ZIP archive of XML parts holding a workbook's sheets, cell values, formulas and formatting, structured under the same Office Open XML standard as DOCX and PPTX, and it has been Excel's default format since Excel 2007.
XLSX at a glance#
| Full name | Microsoft Excel |
|---|---|
| File extension | .xlsx |
| Category | Documents |
| Developer | Microsoft |
| First released | 2007 |
| MIME types | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet |
| Compression | Lossless |
| Specification | ECMA-376 / ISO/IEC 29500 (Office Open XML) |
| FileFlip support | FileFlip reads this format but does not write it |
What a .xlsx file can hold#
These are the things a XLSX file either supports or does not, and they are what decides whether a conversion keeps everything or quietly drops something.
| Embedded metadata | Yes |
|---|---|
| Multiple images or pages | Yes |
| Selectable text | Yes |
| Encryption | Yes |
| Human readable | No |
| Comments | Yes |
| Schema or validation | Yes |
Strengths and limitations of XLSX#
What XLSX does well
- Stores formulas alongside their last computed values, so a workbook still shows numbers immediately on reopening without waiting on recalculation
- Multiple sheets, named ranges and cell formatting all survive together in the same ZIP of XML parts
- Opens in Excel, LibreOffice Calc, Google Sheets and Apple Numbers without a plugin
- Charts reference the underlying cell data directly, so they update automatically when the numbers change
Where XLSX falls short
- Formulas that call Excel-specific functions or add-ins don't always translate correctly when opened in another application
- Reading a workbook as a document flattens each sheet into a plain table, discarding the formulas and recalculation behavior entirely
- A hard limit of 1,048,576 rows per sheet, inherited from Excel itself, applies regardless of which application writes the file
- Macros live in the separate .xlsm variant, so a plain XLSX file can't carry them
Use XLSX for any workbook that still needs formulas, multiple sheets or recalculation, since that behavior only exists while the file stays a spreadsheet.
Convert an XLSX file to a document format when the sheet was really being used to lay out a table for reading, not for calculation, and the destination just needs the values.
How to open a .xlsx file#
A .xlsx file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts XLSX into a format your machine already opens, and it does it in the browser tab rather than on a server.
| Platform | Programs that open it |
|---|---|
| Windows | Microsoft Excel, LibreOffice Calc, WPS Spreadsheets |
| macOS | Microsoft Excel, Apple Numbers, LibreOffice Calc |
| Linux | LibreOffice Calc |
| Web | FileFlip, Google Sheets, Excel Online |
XLSX questions people ask#
What happens to formulas when converting an XLSX file to a document?
Each formula is replaced by whatever value it last calculated to, since a document format has no concept of a spreadsheet formula or recalculation. The number that shows up is correct as of the moment the workbook was saved, but it will never update again after the conversion.
Can I open an XLSX file without Excel?
Yes, Google Sheets, LibreOffice Calc and Apple Numbers all open and save XLSX files natively. Formulas and basic formatting generally survive; Excel-specific add-ins and some advanced chart types are the parts most likely to behave differently elsewhere.
What's the difference between XLSX and CSV?
XLSX keeps multiple sheets, live formulas, cell formatting and data types in one ZIP archive of XML. CSV is a single flat table of plain text values with none of that, which makes it simpler to parse but unable to represent anything a spreadsheet actually calculates.
Why does converting a multi-sheet XLSX file produce more than one table?
Because each sheet in the workbook is its own independent grid of data, converting the file to a document turns every sheet into its own separate table in the output rather than merging them into one.
Converting XLSX files#
Convert XLSX to another format
- XLSX to PDF
- XLSX to AVIF
- XLSX to BMP
- XLSX to DOCX
- XLSX to EPUB
- XLSX to GIF
- XLSX to HTML
- XLSX to ICO
- XLSX to JPEG
- XLSX to JPG
- XLSX to JXL
- XLSX to LaTeX
- XLSX to Markdown
- XLSX to ODT
- XLSX to PNG
- XLSX to PPTX
- XLSX to PSD
- XLSX to RTF
- XLSX to TIFF
- XLSX to TXT
- XLSX to WEBP
- XLSX to AsciiDoc
- XLSX to BBCode
- XLSX to BibTeX
See every XLSX conversion (38 more)
FileFlip does not write .xlsx files, so nothing on the site converts into this format. It works as a source only.
Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.