hi
apparently you are trying to make it WAY more complicated than it really is.
it's simple math....once you understand how xl keeps datea and time
in B1 enter.....=A1+(168/24)
format B1 as date or date+time.
i was going to recomend chip's site but if you have already read it then you
are having trouble grasping the concept.
but here is the site anyway to make sure we're on the same page.
http://www.cpearson.com/excel/datetime.htm

read it again.

Regards
FSt1

"losing it" wrote:

As a relative newbie to excel formulas I'm having great difficulty creating a
formula where I need to add 168 hours to a date/time. After two days of
trying I'm losing my mind :-(

Column A contains the Date/Time (I've tried many formats to no avail) and I
need column B to show the result of adding 168 hours to A1. Any help might
keep from the asylum.

I've have read and re-read Chip Pearson's great work and still can't figure
this out!