We have found 4 software records in our database eligible for .xls to .wk1 file format conversion.
Should you for whatever reason need to convert your Excel spreadsheets (.xls) to a format used in old Lotus 1-2-3 .wk1), the best course of action would be try some older (or better very old) versions of programs like Excel, Quattro Pro etc, because it is very likely that they once could save to the WK1 format, which will essentially achieve xls to wk1 conversion.
It is unlikely that latest versions of commonly available spreadsheet editors still support saving in this format.
XLS
Files with xls extension are best known as spreadsheets from Microsoft Excel. A spreadsheet is basically a grid of cells sorted in rows and columns. Each cell can contain text, numeric or formula data. Excel XLS spreadsheets can be opened in most other similar programs, such as OpenOffice.org Calc.
WK1
Files with wk1 extension are spreadsheets saved in old Lotus 1-2-3 office program. These files were used in version 2.X.