I am getting a Circular reference error when I am writting the following
formula.

=IF(C12< 0,0,(SUM(B12-B7)))


C12 is where I need the answer to go to

B12 is a time stamp where I can enter the time the item was entered or
completed
b7 is the time that the item should have been turned in by.

I am looking to accomplish a Null value if the item is negative which means
ahead of schedule while tracking the positive values if the item was turned
in late.

Any Help would be much appreciated.


Thanks