This is my 3rd post of the day, hopefully last. I was wondering if it is possible to build an calculation for a date. Here is the problem I work in security investigations. a type A clearance is good for 10 from the investigation date. a Type B clearance is good for 5 years from the investigation date then the clearance becomes a Type A clearance for 10 from the investigation date. If I can have this show in a Table great, if not i need to be able to do some time calculations from it like is the clearance going to expire in 180 days, I already have done the is clearance going to expire in 180 days. One more thing is there a decent book out there that teaches some of this stuff that does not cost a lot of money. Thanks