.WK3 File Extension
What is a WK3 file?
Spreadsheet file created by Lotus 1-2-3, version 3; stores data in cells, which are organized into a grid of rows and columns; may be used for a variety of data-entry purposes.
You can open WK3 files with IBM Lotus 1-2-3 and Microsoft Excel. However, IBM Lotus 1-2-3 is discontinued and Excel 2007 and later does not support WK3 files.