Convert XLSB to XLS

A legacy accounting system, office suite, or document-management service may accept only the older .xls format, while a newer workbook may arrive as .xlsb. Saving a copy as XLS provides compatibility, but features introduced after Excel 2003 may be changed or removed.

What the XLSB format is

.xlsb is Microsoft's Excel Binary Workbook format, introduced with Excel 2007. It stores workbook content in a binary BIFF12 structure rather than the XML package used by .xlsx. Binary storage can reduce file size and improve opening, saving, and recalculation speed for some large or calculation-heavy workbooks, although results depend on the workbook.

Microsoft Excel uses XLSB for financial models, operational reports, workbooks with large data sets, extensive formulas, pivot tables, external links, or VBA automation. Current desktop versions of Excel for Windows and macOS can open and save this format.

What the XLS format is

.xls is Excel's legacy Excel 97–2003 Workbook format. It uses the BIFF8 binary structure and remains useful when an older Excel release, accounting application, document system, or office suite cannot read .xlsx or .xlsb.

Each XLS worksheet supports a maximum of 65,536 rows and 256 columns, ending at column IV. Current Excel worksheets support 1,048,576 rows and 16,384 columns, ending at XFD. XLS is therefore a compatibility format, not a suitable target for workbooks that require modern worksheet capacity or features.

How to convert XLSB to XLS

Using Microsoft Excel desktop

1. Open the source workbook, such as budget.xlsb, in desktop Microsoft Excel.
2. Check that no required data lies below row 65,536 or beyond column IV. Move or split data that exceeds those limits before exporting.
3. Select File → Save As, choose a destination, and set the file type to Excel 97–2003 Workbook (*.xls).
4. Use a new filename such as budget.xls, then select Save.
5. Accept Excel's compatibility warning only after reviewing the listed changes. Close and reopen the resulting XLS file to check formulas, formatting, charts, links, and print output.

Excel desktop is generally the safest converter because it is the native application for XLSB. For multiple workbooks, each file normally requires a separate Save As operation; Excel's standard interface does not provide a universal batch-conversion command.

Using LibreOffice Calc

LibreOffice Calc can open many XLSB workbooks and save them through File → Save As with Excel 97–2003 (*.xls) selected. It is a useful offline option, but complex VBA, pivot tables, external connections, charts, and newer formulas may be interpreted less accurately than by Excel.

Using an online converter

Services such as CloudConvert, Zamzar, and Convertio may offer XLSB-to-XLS conversion. Select XLS as the output, upload the workbook, download the result, and inspect it in Excel or LibreOffice. Online service limits and supported formats can change, and uploads may be retained or processed by third parties. Do not use an online converter for confidential financial records, personal data, proprietary formulas, credentials, or regulated documents unless organizational policy explicitly allows it.

Quality and compatibility limits

Saving to XLS can remove or alter features that BIFF8 cannot represent, including data-model content, slicers, some newer conditional-formatting rules, newer chart types, threaded comments, and certain worksheet settings. Excel's compatibility checker lists many affected items before the file is saved.

Formulas generally remain formulas, but functions unavailable in Excel 97–2003 can be changed, produce compatibility errors, or calculate differently. Verify external links, named ranges, pivot tables and caches, charts, page breaks, print areas, page settings, and formula results after conversion.

XLS supports VBA macros, so a macro project can often be retained during the conversion. Code that depends on newer Excel objects, features, references, or workbook structure may still fail. Preserve the original .xlsb, test macros in an isolated copy, and do not enable untrusted macros.

Changing the filename extension does not convert the file. Renaming budget.xlsb to budget.xls leaves the BIFF12 XLSB content unchanged and can make the file unreadable or misidentified.