Hi @Alex_Haney
Simplistically, assuming you have a linked project table, you could get the Projects start week from using a lookup field and then subtract one from the other to give a Project Week. However, using dates formatted as week number doesn’t handle those going over a year end very well.
Alternatively, you could get to it by calculating the number of days from the start of the project to the task date - this seems to work:
INT((DATETIME_DIFF({Task Date}, {Start Date},‘d’)/7) + 1)
Hope this helps!