Convert WK4 to XLS

What the WK4 format is

.wk4 is a binary spreadsheet format associated with Lotus 1-2-3 Release 4 for Windows. A workbook can contain worksheets, formulas, cell formatting, charts, print settings, and other Lotus 1-2-3 data. WK4 files are now mainly found in archives and business records created before Excel became the standard spreadsheet application.

What the XLS format is

.xls is Microsoft Excel's binary workbook format used by Excel 97 through Excel 2003. Many current spreadsheet applications and import systems still support it, making it suitable when a recipient requires the legacy Excel format or uses software that cannot accept .xlsx. XLS is not generally the best format for new workbooks: it has lower worksheet limits and is less efficient than the modern XML-based XLSX format.

How to convert the file

Using LibreOffice Calc

1. Install LibreOffice from libreoffice.org and open Calc.
2. Choose File → Open, select the WK4 file, and let Calc use its Lotus 1-2-3 import filter.
3. Inspect every relevant sheet, including formulas, dates, number formats, column widths, hidden rows or columns, print areas, and charts.
4. Choose File → Save As, select Excel 97–2003 (*.xls) as the file type, and save to a new filename such as converted.xls.
5. If Calc warns that some content may not be preserved, choose Use Excel 97–2003 Format, not the OpenDocument format.

LibreOffice Calc is the most practical first option because it runs locally and its Calc filters can import many WK4 files without exposing the workbook to a third party. If Calc cannot read a particular file, try Lotus 1-2-3 Release 4 or 5, or Microsoft Excel 97–2003 with its Lotus import support, if that legacy software is available. Open the file there and use File → Save As to select the Excel 97–2003 format.

Using an online converter

Online services such as Zamzar sometimes provide direct WK4-to-XLS conversion. On the service's current format page, confirm that WK4 is accepted and XLS is offered as the output; support lists can change. Upload the file, choose XLS, start the conversion, and download the result. Do not upload confidential, personal, regulated, or proprietary workbooks unless the service's privacy and retention terms are acceptable.

Quality and compatibility limits

Import filters may alter Lotus-specific formulas, macros, named ranges, external links, charts, fonts, page breaks, print settings, and date or number formatting. Formula syntax can translate differently even when the displayed values look correct, so compare important totals and recalculate the workbook in the target application. Inspect each worksheet rather than checking only the first tab.

Each XLS worksheet supports a maximum of 65,536 rows and 256 columns. A WK4 sheet exceeding either limit cannot be represented completely in one XLS worksheet; split the data or use XLSX if the receiving system permits it. Keep the original WK4 file, save the converted copy under a different name, and verify that the resulting XLS opens correctly before archiving or distributing it.