We have found 4 software records in our database eligible for .xlsm to .wk1 file format conversion.
xlsm to wk1 conversion is perhaps still doable, but it's pretty much export of modern MS Excel spreadsheet with macros (.xlsm) to some ancient format used in Lotus 1-2-3 (.wk1 files). Some spreadsheet editors still support formats from Lotus 1-2-3, so this is technically doable, but it will only work for data and certainly not for any formatting that might be part of .xlsm files.
Updated: March 13, 2023
XLSM
Files with xlsm extension are used for workbooks of spreadsheets created in Microsoft Excel that also include macros, that enhance the functionality of the spreadsheet but some automation features. Other spreadsheets might open xlsm files as well, however they most likely wont be able to use the Excel specific formatting and macros.
WK1
Files with wk1 file extension are spreadsheets saved in old Lotus 1-2-3 office program. These files were used in version 2.X.