Convert WK3 to XLS

An archived Lotus 1-2-3 spreadsheet may need conversion because a current spreadsheet program, reporting system, or business workflow accepts Excel's .xls format but cannot read .wk3. Conversion also allows recipients without Lotus software to edit and share the data.

What the WK3 format is

WK3 is the binary worksheet format associated with Lotus 1-2-3 Release 3, an older spreadsheet application used mainly on DOS and early Windows systems. Files can contain values, formulas, cell formatting, ranges, charts, print settings, and other worksheet structures. They are now most often found in archived accounting records, business backups, and legacy databases.

Current versions of Microsoft Excel do not reliably open WK3 files directly, and support in modern spreadsheet software can vary by version and operating system.

What the XLS format is

XLS is Excel's binary workbook format used primarily by Excel 97 through Excel 2003. Microsoft Excel, LibreOffice Calc, Apache OpenOffice Calc, and many older business systems can read it. XLS is appropriate when the receiving system specifically requires Excel 97–2003 format or must interoperate with legacy Excel software.

Use XLSX for new workbooks unless the destination requires XLS. XLSX supports newer Excel features and uses a modern XML-based structure, while XLS has a smaller worksheet and feature limit.

How to convert a WK3 file to XLS

Using LibreOffice Calc

1. Install a current desktop version of LibreOffice from the official LibreOffice website.
2. Open Calc and select File → Open.
3. Select the .wk3 file. Set the file filter to All files if the file is not shown.
4. Review the imported values, formulas, dates, formatting, charts, column widths, and print settings.
5. Select File → Save As.
6. Choose Excel 97–2003 (.xls), provide a filename ending in .xls, and select Save.
7. When Calc warns about format or feature loss, choose Use Excel 97–2003 Format.

Calc is a practical first option because it can import several Lotus 1-2-3 formats without the original Lotus application. For multiple files, a basic headless conversion can be run from a shell:

soffice --headless --convert-to xls --outdir converted *.wk3

Test the graphical conversion first, because supported input filters and output filter names can differ between LibreOffice releases. The command writes the converted files to the converted directory; create that directory before running it.

Using a dedicated converter

A Windows utility such as ABC Amber Lotus Converter is designed for older Lotus worksheet formats and may export WK3 files directly to XLS. Check the developer's current format list and trial the software on a copy of the file before buying or processing a large archive. These legacy converters can differ in their handling of charts, formulas, and formatting.

If Calc and a dedicated converter both reject the file, a licensed copy of a compatible Lotus 1-2-3 release may be required to open and resave it before exporting. Do not overwrite the original WK3 file.

Using an online converter

Online services such as Zamzar and CloudConvert can be considered only if their current upload page explicitly lists .wk3 as an accepted input and .xls as an output. Upload the file, select XLS, run the conversion, and download the result. Support for obsolete formats can be removed without notice, so an online service should not be treated as a guaranteed WK3 converter.

Do not upload confidential financial, personal, or regulated data unless the service's storage, retention, deletion, and transfer terms satisfy your requirements. Desktop conversion is safer for sensitive archives.

Quality and compatibility checks

Successful export does not prove that the workbook is identical. Lotus 1-2-3 formulas, date serials, charts, macros, named ranges, external links, print settings, and formatting may not map exactly to Excel's model. Some formulas may be changed, unsupported features may be discarded, and macros will not automatically become functioning Excel VBA code.

• Compare totals and key formulas with the original.
• Check dates for incorrect day/month interpretation, shifted years, or changed date values.
• Inspect charts, merged cells, borders, page breaks, row heights, and column widths.
• Test named ranges, external links, and print areas.
• Open the resulting XLS in the program that will receive it, not only in Calc.

Keep the original WK3 file unchanged as the archival copy and retain the converted XLS as a separate working file.