Format guide
What is XLSX?
Office Open XML Spreadsheet is a Microsoft Excel Open XML workbook for spreadsheets, formulas, and charts, created by Microsoft (2007). XLSX is the business default for spreadsheets: multiple sheets, formulas, pivot-friendly data, and formatting. Use CSV when you only need raw values for import, and PDF when you need a non-editable snapshot of a report.
XLSX format specifications
- Full name
- Office Open XML Spreadsheet
- Kind
- spreadsheet
- File extension
- .xlsx
- MIME type
- application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
- Developer / standard
- Microsoft · 2007
- Compression
- none or container
- Quality model
- Lossless / not lossy
- Container
- No / single bitstream typical
- Common codecs
- —
- Technical sources
- —
- Transparency
- Not supported
- Animation
- No (still / non-animated typical use)
- Typical size
- Small to large depending on data and embedded images
- Browser support
- Edit via Sheets/Excel online; not a native browser grid format
- Compatibility
- Opens in Excel, Google Sheets, LibreOffice Calc, and Numbers with occasional formula quirks — the spreadsheet exchange default
XLSX compression & quality
XLSX compression: none or container. Lossless (or non-destructive packaging) keeps reconstructable data — size savings come from packing efficiency, not throwing detail away. Typical size profile: Small to large depending on data and embedded images. Quality note: Full spreadsheet fidelity in Excel-compatible apps
Quality: Full spreadsheet fidelity in Excel-compatible apps
Typical size: Small to large depending on data and embedded images
Transparency & animation
XLSX does not support an alpha channel. Convert to PNG, WebP, AVIF, or SVG when you need transparent backgrounds.
XLSX is a still-media or non-animated format in typical use. Use GIF, APNG, video, or animated WebP when you need motion.
XLSX metadata
Workbook properties and sometimes defined names/comments; not a substitute for proper data lineage docs.
Best use cases for XLSX
- Financial models
- Operational trackers
- Formatted reports
- Data analysis in Excel/Sheets
- Sharing workbooks with businesses
When to avoid XLSX
- Huge raw dumps better left as CSV/database tables
- Final legal records that must not change (use PDF)
- Simple lists that do not need formulas
- Binary storage of unrelated documents
Advantages
- Industry spreadsheet standard
- Formulas and multiple sheets
- Formatting and charts
- Huge add-in ecosystem
- Familiar to finance and ops teams
Disadvantages
- Formula compatibility quirks across apps
- Easy to corrupt with bad generators
- Macros can be risky
- Unwieldy for massive data
Compatibility
Opens in Excel, Google Sheets, LibreOffice Calc, and Numbers with occasional formula quirks — the spreadsheet exchange default
Browsers: Edit via Sheets/Excel online; not a native browser grid format
Software support
- Microsoft Excel
- Google Sheets
- LibreOffice Calc
- Format Convertly
Device support
- Desktops and office mobile apps
- Modern desktops
- Phones and tablets with compatible apps
How to open XLSX
Open in Excel or upload to Google Sheets. For stubborn imports, save a CSV values copy as a fallback.
How to convert XLSX
Convert XLSX to CSV for database imports or to PDF for read-only reports using Format Convertly’s private in-browser tools.
Popular XLSX conversions
Convert to XLSX
Incoming conversions strengthen the XLSX cluster — e.g. JPG → XLSX, PNG → XLSX.
XLSX comparison guides
Compare XLSX with related formats to pick the right container for quality, size, and compatibility.
Best format guides featuring XLSX
Decision pages that cite XLSX — the next hop after a vs comparison.
XLSX how-to guides
Related formats
XLSX tools
Tools extend the format graph beyond one-off conversion — compression, metadata, and utilities for real workflows.
XLSX FAQ
What is a XLSX file?
XLSX is a Microsoft Excel Open XML workbook for spreadsheets, formulas, and charts. XLSX is the business default for spreadsheets: multiple sheets, formulas, pivot-friendly data, and formatting. Use CSV when you only need raw values for import, and PDF when you need a non-editable snapshot of a report.
Is XLSX lossy or lossless?
XLSX is typically lossless or non-destructive in common use (none or container).
Does XLSX support transparency?
XLSX does not support an alpha channel. Convert to PNG, WebP, AVIF, or SVG when you need transparent backgrounds.
How do I open a XLSX file?
Open in Excel or upload to Google Sheets. For stubborn imports, save a CSV values copy as a fallback.
How do I convert XLSX privately?
Convert XLSX to CSV for database imports or to PDF for read-only reports using Format Convertly’s private in-browser tools. Format Convertly keeps processing in your browser so files are not uploaded to a conversion server.
Are my XLSX files uploaded on Format Convertly?
No. XLSX conversion runs in your browser. Files are not sent to Format Convertly servers for processing.