Convert BAK to XLS

Converting .bak files (numerous different backup file types using .bak suffix exist) directly to Microsoft Excel Spreadsheets (.bak to .xls conversion) is only possible if your backup files contain some sort of table data, spreadsheet or database.

Certain software merely rename the suffix from .bak, so a .bak to .xls conversion wouldn't be necessary. You would only have to rename the file back to its original format; in this case .xls.

Should those attempts fail, you won't be left with many alternatives to reliably convert the files. The .bak format is too frequent to be able to provide more specific details. That would always depend on what software your .bak file is associated with.