I have two main date fields and I want to track the number of days between them.

Imagine "Open" and "Closed" dates, where my "Number of Days" will equal the difference between "Open" and Today's date, until I input a "Closed" date.

I'm putting together an If statement using Null, but I'm not quite there yet. Formula is below:

If(IsNull(ToDays([Pit Backfilled On]-[Pit Open Date]),ToDays(Today()-[Pit Open Date])))

Thank you!