Calculated column between two date fields but if one is blank use another date field

Question

I would like a calculation that gives the number of days between 2 dates (start date & end date) but if end date is blank I would like it to use todays date. How can I set this formula up?

Answer 1

This should do the trick:

=IF(ISBLANK([EndDate]),DATEDIF([StartDate], Today(),"d"),DATEDIF([StartDate], [EndDate],"d"))