Tableau doesn't have a "work week" concept. Just a calendar concept and a week concept.
I would create two calcs here. One to assign a "work month" that fits your business model. And another to assign a "work week" number (1-through-4 (or 5) ) so that you can deal with these in your reports as a dimensional field.
(Just curious. Could a work week also look forward. For instance if the first day of the week in a particular month is the 31st of the month, could that week be considered to fall in the following month?)
I have already applied a work week number. I guess I just need to assign a month as well. I was hoping there was a calculation for this instance.
I hadn't considered the look forward idea. Logically it should be added to the next month. This does create anomalies.
Thanks for your reply.