Free online WK1 to EXCEL converter

Older Lotus 1-2-3 spreadsheets may need conversion because current Microsoft Excel versions do not reliably open the original .wk1 format. Converting the file creates an .xlsx or .xls workbook that current spreadsheet software can edit, share, and archive.

What the WK1 format is

.wk1 is a worksheet format used by Lotus 1-2-3, particularly versions 2.x and 3.x for DOS and early Windows systems. It stores cells, formulas, basic formatting, and other worksheet data. WK1 files are most likely to appear in records from older businesses, accounting systems, engineering projects, and personal computers.

What the EXCEL format is

EXCEL refers to Microsoft Excel workbook formats rather than one specific extension. .xls is the older Excel 97–2003 binary format, while .xlsx is the XML-based format used for current Excel workbooks. Excel formats support larger worksheets, newer formulas, filtering, charts, and broader compatibility with current spreadsheet applications.

Choose .xlsx for current Excel and other modern spreadsheet software. Choose .xls only when a legacy application specifically requires Excel 97–2003 format.

How to convert WK1 to EXCEL

Using the 101convert.com converter

1. Open the WK1-to-EXCEL converter on 101convert.com.
2. Upload the .wk1 file.
3. Select .xlsx for current software or .xls for an application that requires the older Excel format.
4. Start the conversion and download the generated workbook.
5. Open the result in Excel, LibreOffice Calc, or another spreadsheet application.
6. Check formulas, dates, column widths, formatting, and important totals against the original file.

The online converter can process the file without installing desktop software. Do not upload confidential or regulated data unless the service's current handling and retention terms meet your requirements.

Using LibreOffice Calc

1. Install and open LibreOffice Calc.
2. Select File → Open and choose the .wk1 file. If automatic detection fails, select the Lotus 1-2-3 worksheet filter in the file-type list.
3. Review the imported worksheet, especially formulas, dates, number formats, and layout.
4. Select File → Save As.
5. Choose Excel 2007–365 (.xlsx) or Excel 97–2003 (.xls), then save a new copy.
6. Reopen the saved workbook in the intended Excel version and verify the results.

Quality and compatibility limits

WK1 is an obsolete format, so conversion can change Lotus-specific formulas, number formats, print settings, cell borders, named ranges, charts, or other worksheet objects. Formulas using Lotus 1-2-3 syntax may import incorrectly, become values, or require manual rewriting. Large or damaged files may not convert completely.

Keep the original WK1 file unchanged and compare key totals with a trusted copy or printout. If formulas, charts, or layout are business-critical, inspect every worksheet after conversion rather than relying only on whether the output opens successfully.