How to add a formula to a view's criteria

I know there are formula fields that can be added to a form, but how would I add a formula to the criteria of a view?

For instance. We have a field in our Contacts form that is the date they joined our program.

I need to find all of the contacts that are due for renewal today. So if they joined on Dec. 15,2012 the formula would return the value of 15.

The formula I want to use is "Dayofmonth(${Contacts.Payment Start Date})" but I can't see where to use that when defining a view's criteria.

Any help appreciated.

Kerry