Lotus 3 Worksheet (.wk3)
The WK3 file format is a Lotus 3 Worksheet file used by Lotus 1-2-3 version 3. It stores data in cells organized into rows and columns and can be opened with IBM Lotus 1-2-3 and Microsoft Excel. However, IBM Lotus 1-2-3 is discontinued and Excel 2007 and later do not support WK3 files.