General

ODS: The Open Spreadsheet Format

Published Mar 19, 2026 6 min read By ChangeThisFile Team

Quick Answer

ODS (OpenDocument Spreadsheet) is the ISO/IEC 26300 standard for spreadsheets, the default format in LibreOffice Calc and Apache OpenOffice. It uses a ZIP of XML files (similar to XLSX) and supports formulas, formatting, charts, and pivot tables. Government mandates in the EU, UK, and several countries require ODS for public documents. XLSX compatibility is good for data and basic formulas but degrades for charts, macros, and advanced conditional formatting.

ODS exists because governments and international standards bodies decided that the world's most common document formats shouldn't be controlled by a single company. The OpenDocument Format (ODF) was developed by OASIS, approved as ISO/IEC 26300 in 2006, and mandated by multiple governments for public sector documents. ODS is the spreadsheet component of ODF, alongside ODT (text) and ODP (presentations).

In practice, ODS lives in the shadow of XLSX. Microsoft Office has 80%+ market share, and most people never consciously choose ODS. But ODS is the default format for the millions of LibreOffice and OpenOffice users worldwide, it's required in government contexts across Europe, and it's a genuinely capable format that handles most spreadsheet tasks. If you receive an ODS file or need to produce one, here's what you need to know.

Inside an ODS File: ZIP of XML (Just Like XLSX)

ODS files share the same basic architecture as XLSX: a ZIP archive containing XML files. Rename .ods to .zip, extract, and you'll find:

spreadsheet.ods/
├── META-INF/
│   └── manifest.xml    (file listing and MIME types)
├── mimetype            (plain text: "application/vnd.oasis.opendocument.spreadsheet")
├── content.xml         (all cell data, formulas, and structure)
├── styles.xml          (named styles and page layouts)
├── meta.xml            (author, creation date, statistics)
└── settings.xml        (view settings, print settings)

The key structural difference from XLSX: ODS stores all sheet data in a single content.xml file, while XLSX uses separate XML files per worksheet. For small files, this doesn't matter. For large files with multiple sheets, it means ODS's content.xml can become enormous, and you can't selectively parse a single sheet without loading the entire file.

ODS formulas use the OpenFormula specification (OASIS), which defines functions in a namespace-prefixed syntax: of:=SUM([.A1:.A100]). Cell references use square brackets and dots. In practice, LibreOffice displays these in a user-friendly format identical to Excel's syntax, but the stored format is different.

Government Mandates and Why ODS Matters Politically

ODS isn't just a technical alternative to XLSX — it's a policy instrument. Governments mandate ODS to prevent vendor lock-in and ensure long-term document accessibility:

European Union: The European Interoperability Framework recommends ODF for document exchange between EU institutions and member states.
United Kingdom: Since 2014, the UK government mandates ODF for sharing editable government documents. The Government Digital Service explicitly chose ODF over OOXML (XLSX/DOCX) to avoid dependency on Microsoft.
France: The General Interoperability Framework (RGI) mandates ODF for government document exchange.
Germany: Multiple federal states mandate ODF. The state of Munich famously migrated 15,000 government desktops to LibreOffice (later partially reversed).
India: The Indian government adopted ODF as the standard for e-governance documents.
NATO: NATO STANAG 4774 specifies ODF for document exchange.

If you work with government agencies in these jurisdictions, you may be required to submit spreadsheets in ODS format. Converting XLSX to ODS is the typical path, and understanding what survives the conversion prevents rejection of your submission.

XLSX Compatibility: What Works and What Breaks

LibreOffice Calc can open and save XLSX files directly, and Excel can open ODS files (since Office 2007 SP2). But "can open" doesn't mean "renders identically." Here's a feature-by-feature compatibility breakdown:

Feature	ODS → XLSX	XLSX → ODS
Cell values and text	Perfect	Perfect
Number formatting	Good (95%+)	Good (95%+)
Basic formulas (SUM, IF, VLOOKUP)	Perfect	Perfect
Advanced formulas (XLOOKUP, LET, LAMBDA)	N/A (LibreOffice doesn't have these)	Become errors or static values
Conditional formatting	Basic rules work; complex rules may differ	Basic rules work; icon sets may differ
Charts	Simple charts ok; complex charts redrawn differently	Same — rendering differences are common
Pivot tables	Partial — may need recreation	Partial — data preserved, structure may shift
Macros (VBA ↔ LibreOffice Basic)	Not compatible	Not compatible
Data validation	Good	Good
Images and shapes	Usually preserved, positioning may shift	Usually preserved, positioning may shift

Formula Translation Details

The core spreadsheet functions — arithmetic, logic (IF, AND, OR), lookup (VLOOKUP, HLOOKUP, INDEX, MATCH), text (LEFT, RIGHT, MID, CONCATENATE), date (DATE, TODAY, YEAR, MONTH), and statistical (AVERAGE, COUNT, COUNTIF, SUMIF) — translate perfectly between ODS and XLSX. These cover 95% of real-world formula usage.

The gaps are in newer Excel-specific functions:

XLOOKUP, XMATCH — Added to Excel 365. LibreOffice doesn't support them. Converting XLSX with these to ODS produces #NAME? errors.
LET, LAMBDA — Excel 365 functions for named variables and custom functions. No ODS equivalent.
SORT, FILTER, UNIQUE, SEQUENCE — Excel dynamic array functions. LibreOffice has partial implementations (SORT works, FILTER works differently, UNIQUE isn't available in all versions).
TEXTJOIN, CONCAT — LibreOffice supports these since version 6.0, but older versions don't.

LibreOffice also has functions Excel doesn't: STYLE(), CURRENT(), and several statistical functions from the OpenFormula specification. These become errors or static values when converting ODS to XLSX.

When ODS Is Required

Use ODS when:

Government submission requires it. UK, EU, French, or Indian government agencies may reject XLSX submissions.
Your organization uses LibreOffice. Working natively in ODS avoids the conversion overhead and compatibility risks of constantly round-tripping through XLSX.
Long-term archival. ODS is an ISO standard with a publicly available specification. Even if LibreOffice disappears tomorrow, any competent developer can write an ODS parser from the spec. XLSX is also standardized (ECMA-376 / ISO 29500), but the spec is 6,000+ pages and the practical implementation depends on Microsoft's interpretation.
Avoiding vendor lock-in is a policy goal. If your organization wants to ensure that documents remain accessible without specific commercial software, ODS is the answer.

When XLSX Is the Better Choice

Use XLSX when:

Most recipients use Excel. XLSX will render exactly as intended in Excel. ODS in Excel may have chart, formatting, or formula differences.
You use Excel-specific features. Dynamic arrays, Power Query, Power Pivot, VBA macros, and threaded comments are XLSX-only. There's no ODS equivalent.
Third-party integrations expect XLSX. Most SaaS tools, BI platforms, and data import features accept XLSX. Fewer accept ODS.
Chart fidelity matters. Excel's chart engine is more advanced than LibreOffice's, and XLSX preserves chart formatting more reliably than ODS for Excel-originated charts.

The pragmatic approach: work in whatever format your primary tool uses (XLSX for Excel, ODS for LibreOffice) and convert when sharing. XLSX to ODS for government submissions. ODS to XLSX for Excel users. Test the converted file in the target application before sending.

Conversion Tips: ODS to XLSX and Back

When converting between ODS and XLSX, follow these practices to minimize issues:

Test formulas after conversion. Open the converted file and check that formula cells show correct values, not #NAME? or #VALUE! errors. Pay special attention to array formulas and functions added after 2019.
Verify charts visually. Charts are the most common casualty. Colors, labels, axis formatting, and data series may shift. If chart appearance is critical, consider converting the chart to an image before converting the file.
Check conditional formatting. Open a few cells that should be conditionally formatted and verify the rules are applied. Icon sets and data bars are the most likely to differ.
Macros don't convert. VBA (Excel) and LibreOffice Basic are different languages. Converting a file doesn't translate the macro code. If macros are essential, they must be manually rewritten for the target platform.
Pivot tables may need rebuilding. The pivot table data usually survives, but the configuration (field layout, calculated fields, grouping) may not. Refresh the pivot after conversion and verify the layout.

For data interchange without formatting concerns, bypassing the ODS/XLSX conversion entirely is cleaner: export ODS to CSV or export ODS to JSON, then import into the target application.

ODS is the format that exists because open standards matter. It's technically capable, well-specified, and backed by an international standard. It's also perpetually playing catch-up with Excel's feature set, because Microsoft has more resources to add features than the LibreOffice community does to implement them.

For most individual users, the format choice is dictated by their tool: Excel users work in XLSX, LibreOffice users work in ODS, and conversion happens at the boundaries. The important thing is knowing where those boundaries cause friction — charts, macros, and advanced formulas — and testing conversions before they reach the recipient.

Key Takeaways

ODS is an ISO standard (ISO/IEC 26300) for spreadsheets, the default format for LibreOffice Calc, and mandated by several governments for public documents.
Like XLSX, ODS is a ZIP of XML files. The main structural difference: ODS stores all sheets in one content.xml, while XLSX uses separate XML files per sheet.
Core formulas (SUM, IF, VLOOKUP, INDEX/MATCH) translate perfectly between ODS and XLSX. Excel-specific functions (XLOOKUP, LAMBDA, dynamic arrays) become errors in ODS.
Charts and conditional formatting are the most common compatibility casualties. Always verify visually after converting between ODS and XLSX.
Macros don't translate. VBA (Excel) and LibreOffice Basic are completely different languages.
Use ODS when government mandates require it, for long-term archival, or when working natively in LibreOffice. Use XLSX when sharing with Excel users.

Frequently Asked Questions

Can Microsoft Excel open ODS files?

Yes, since Office 2007 Service Pack 2. Excel can open, edit, and save ODS files directly. However, features that Excel doesn't support natively in ODS (like certain LibreOffice-specific functions) may produce errors or be silently converted to values. Excel's ODS support is functional but not as polished as its native XLSX handling — occasional formatting differences are expected.

Is ODS or XLSX better for long-term archival?

ODS has a slight advantage for archival because its specification is shorter (700 pages vs. 6,000+ for OOXML), more consistently implemented, and developed by a multi-vendor standards body rather than a single company. Both are ISO standards, both are ZIP-of-XML formats, and both can be parsed without proprietary software. For maximum archival safety, save in both formats, or save as CSV/PDF alongside the original for guaranteed long-term readability.

Why does the UK government mandate ODS over XLSX?

The UK Government Digital Service chose ODS to avoid vendor lock-in. Their reasoning: government documents should be accessible without requiring specific commercial software. While XLSX is technically an open standard too, the UK assessed that ODS was more truly vendor-neutral, with multiple independent implementations (LibreOffice, Apache OpenOffice, Google Sheets) and no single dominant vendor controlling the specification's direction.

Do Google Sheets support ODS?

Yes. Google Sheets can open ODS files (upload to Google Drive, open with Google Sheets) and export to ODS (File > Download > OpenDocument Format). The compatibility is similar to XLSX: standard formulas and formatting work, Google-specific functions (QUERY, IMPORTRANGE) aren't available in ODS, and chart rendering may differ.

What happens to VBA macros when converting XLSX to ODS?

VBA macros are completely stripped. There is no automatic translation from VBA to LibreOffice Basic — the languages, object models, and APIs are different. When you convert an XLSX with macros to ODS, the data and formulas survive but all VBA code is removed. If the macros are essential, they must be manually rewritten in LibreOffice Basic or Python (which LibreOffice also supports as a macro language).

Is ODS performance worse than XLSX for large files?

Generally yes. ODS stores all sheets in a single content.xml file, which means the parser must load the entire file to access any sheet. XLSX uses separate XML files per sheet, allowing selective loading. For a 100MB workbook with 10 sheets, accessing one sheet in XLSX requires parsing ~10MB of XML. In ODS, it requires parsing the full 100MB content.xml. LibreOffice's ODS handling is well-optimized, but the architectural difference creates an inherent disadvantage for very large files.

How do I convert ODS to XLSX in bulk?

LibreOffice command-line is the fastest method: <code>libreoffice --headless --convert-to xlsx *.ods</code> converts all ODS files in the current directory to XLSX. For individual files, <a href='/ods-to-xlsx'>convert ODS to XLSX on ChangeThisFile</a>. In Python, you can use the odfpy library to read ODS and openpyxl to write XLSX, though LibreOffice's converter handles formatting and formulas better than most programmatic approaches.

Can I use ODS for data analysis in Python or R?

Yes, but library support is weaker than for CSV or XLSX. In Python, <code>pandas.read_excel('file.ods', engine='odf')</code> reads ODS files using the odfpy engine. In R, the readODS package handles ODS files. However, both are slower and less tested than their CSV/XLSX equivalents. For data analysis, converting <a href='/ods-to-csv'>ODS to CSV</a> first and then reading the CSV is often more reliable.

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