What is the difference between XLS and ODS?

XLS is the pre-2007 Excel binary workbook format. It is still emitted by legacy systems and older export routines, and remains readable by current spreadsheet software, though support is being phased out in favour of XLSX. ODS is the OpenDocument spreadsheet format used natively by LibreOffice Calc. It is an ISO standard and a ZIP container of XML, carrying multiple sheets, formulas and formatting much as XLSX does.

Will I lose anything converting XLS to ODS?

No. Both formats represent the same data model, so the values and their structure come across intact. Excel reads ODS but its support for some formula functions differs, so complex workbooks can show errors after a round-trip.

Anything to watch out for with ODS?

Excel reads ODS but its support for some formula functions differs, so complex workbooks can show errors after a round-trip. Converting ODS to CSV, as with XLSX, exports a single sheet as computed values.

What happens to formulas?

Formulas are carried across between workbook formats.

What if my workbook has multiple sheets?

All sheets are preserved — both formats are multi-sheet containers.

What should I know about starting from XLS?

XLS is the pre-2007 binary format, capped at 65,536 rows and 256 columns per sheet, and increasingly deprecated by the software that reads it. More broadly: XLS is the legacy Excel binary format, the default until Office 2007. It is still produced by older enterprise systems and by export routines nobody has revisited in fifteen years.

When is ODS the right choice?

ODS suits: open-source and public-sector workflows where ODF is mandated; avoiding a dependency on Microsoft formats. It is the wrong choice when sharing with people who only have Excel, where XLSX avoids any conversion step.

Is there a file size limit?

No hard limit — the constraint is your browser's memory. Files under 50MB convert in a few seconds. Larger files work but take longer, and a browser tab typically has 250-500MB to play with, so very large batches are better split into smaller groups.

Does this work on mobile?

Yes. The drop zone falls back to your phone's file picker, and the conversion runs on-device exactly as it does on desktop. Large files are slower on a phone because there is less CPU and memory available, but nothing about the workflow changes.

Convert XLS to ODS

Convert legacy XLS workbooks to ODS, lifting the old 65,536-row ceiling. Free, in your browser, no upload.

Drop spreadsheet files to convert

XLSX, XLS, ODS, CSV

Files stay on your device. Open DevTools' Network tab to verify.

Overview

Why convert XLS to ODS

ODS is the more practical choice here. Open-source and public-sector workflows where ODF is mandated

Comparison

XLS vs ODS: what actually differs

XLS compared with ODS across encoding, fidelity, file size and support.
Attribute	XLS	ODS
Full name	Excel Binary Interchange Format	OpenDocument Spreadsheet
Encoding	Binary	Binary
What it preserves	Multiple sheets and formulas, with older limits	Full — multiple sheets, formulas, formatting
Typical size	Larger than XLSX for the same content — no ZIP container	Comparable to XLSX
Support	Read by Excel, LibreOffice and Google Sheets; increasingly deprecated.	Native in LibreOffice and OpenOffice; read by Excel and Google Sheets.

How to

How to convert XLS to ODS

01
Drop your XLS file
Drag one or more XLS files onto the drop zone above, or click to browse. Files stay on your device — there is no upload step.
02
Convert to ODS
convert.now parses the XLS and writes it out as ODS in a Web Worker, so the page stays responsive even on large files. Nothing is sent anywhere.
03
Download the result
Download the ODS file, or a zip of all of them for a batch. Filenames are preserved, with the extension changed to .ods.

Why here

Why convert.now

Private
Files stay in your browser. No upload step. Nothing for anyone to see.
Fast
No queue, no upload wait. Conversion starts the moment you drop a file.
Free
No ads. No file-count limit. No sign-up wall. Just the converter.

FAQ

XLS to ODS: common questions

No. The XLS to ODS conversion runs entirely in your browser. Files never leave your device, and there is no server involved in the conversion at all. Open DevTools' Network tab and run a conversion if you want to confirm it — you will see the page and its code load, and no request carrying your file.

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Last updated 27 August 2026

Why convert XLS to ODS

XLS vs ODS: what actually differs

How to convert XLS to ODS

Drop your XLS file

Convert to ODS

Download the result

Why convert.now

XLS to ODS: common questions

Related XLS converters