Document Format Comparison

XLS vs ODS — Excel Binary vs OpenDocument Spreadsheet

XLS is Microsoft's binary spreadsheet format from Excel 97–2003 — proprietary and closed. ODS is the OpenDocument Spreadsheet format used by LibreOffice Calc and Apache OpenOffice — open standard, ISO certified. Both are mostly legacy now: XLS gave way to XLSX in 2007, ODS gave way to XLSX as the de facto standard for cross-platform sharing.

XLSvsODS

Quick Verdict

Use XLS when…

Don't use XLS — it's legacy. Convert to XLSX for modern use, or to ODS if you're committed to LibreOffice.

Use ODS when…

Use ODS if you work in LibreOffice and don't share files with Excel users. For interchange, use XLSX (Excel) or CSV (universal).

XLS vs ODS: Feature Comparison

Feature	XLS	ODS
Format type	Microsoft binary	Open standard ZIP+XML
Maximum rows	65,536	1,048,576
Excel compatibility	Native (legacy)	Imported with mild fidelity loss
LibreOffice compatibility	Imported with fidelity loss	Native
Macros	VBA (binary)	BASIC (text)
Modern relevance	Legacy — use XLSX	LibreOffice users only

When XLS wins

✓Format type: Microsoft binary
✓Maximum rows: 65,536
✓Excel compatibility: Native (legacy)

When ODS wins

✓Format type: Open standard ZIP+XML
✓Maximum rows: 1,048,576
✓Excel compatibility: Imported with mild fidelity loss

Frequently asked questions

Which is more open: XLS or ODS?

ODS — it's an ISO-certified open standard (ISO/IEC 26300). XLS is Microsoft's reverse-engineered binary format — Microsoft published the spec in 2008, but the format itself is proprietary by design. For long-term archival, ODS or XLSX are better than XLS.

Can Excel open ODS files?

Yes — Excel 2010 and later open ODS files natively. Some advanced ODS features (custom formula extensions, embedded BASIC macros) may not import cleanly. For perfect compatibility, save as XLSX in LibreOffice when sharing with Excel users.