Hi Phyllis. I’m not sure what you are trying to do but you can’t define a custom field as both a looking table and a formula. Try this. Create a new Group (View, Group, New Group by) . Enter Start as the Field Name, and then go to the “Define Group Intervals button under the Group by settings. Their you can set Group On to Months and the Start at to the first of the month. I think that should get you what you are looking for…?? Hope that helps.