Free online WK4 to EXCEL converter

Legacy Lotus 1-2-3 files may be unreadable in current spreadsheet software, while Microsoft Excel workbooks are needed for editing, reporting, and sharing. Converting .wk4 to .xlsx or .xls makes the spreadsheet usable in current Excel and compatible office suites.

What the WK4 format is

.wk4 is a proprietary binary spreadsheet format associated with Lotus 1-2-3 Release 4 for Windows. It can contain worksheet cells, formulas, formatting, charts, and other spreadsheet objects. WK4 files are mainly found in business archives created before Microsoft Excel became the standard spreadsheet application.

What the EXCEL format is

Modern Excel workbooks normally use .xlsx, an XML-based format supported by Microsoft Excel, LibreOffice Calc, and other current spreadsheet programs. The older binary .xls format is appropriate when the recipient uses an old Excel release or software that cannot process XLSX. XLSX supports larger worksheets than XLS and is generally better suited to current software, while XLS may preserve compatibility with older systems.

How to convert WK4 to EXCEL

Using LibreOffice Calc

1. Install and open LibreOffice Calc.
2. Select File → Open, choose the .wk4 file, and let Calc import it.
3. Inspect representative worksheets, formulas, dates, totals, and formatted ranges for import errors.
4. Select File → Save As.
5. Choose Excel 2007–365 (*.xlsx), specify a new filename, and save the workbook.
6. If Calc displays a format warning, select Use Excel 2007–365 Format.

Choose Excel 97–2003 (*.xls) instead when the destination system requires the older Excel format. Keep the original WK4 file unchanged until the output has been checked.

Using the built-in online converter

You can convert a WK4 file on 101convert.com for free without installing software. Open the WK4 converter, upload the file, select Excel as the output format, start the conversion, and download the resulting workbook. Open the downloaded file in Excel or Calc and verify its contents before using it as the only copy.

Quality and compatibility limits

Cell values, worksheets, common formulas, and basic formatting often transfer successfully, but conversion is not guaranteed to reproduce every Lotus 1-2-3 feature. Macros, add-ins, unusual formula functions, print settings, named ranges, charts, and other embedded objects may be omitted, changed, or imported with different behavior because WK4 and Excel use different spreadsheet models.

After conversion, recalculate formulas, compare important totals with the WK4 source, inspect date and currency formats, and check chart ranges and page layout. If Calc cannot open the file or formulas import incorrectly, use a Lotus 1-2-3-compatible application to open and resave the file in an intermediate spreadsheet format, then create the final .xlsx or .xls workbook.