Jon Peltier has instructions for adding a horizontal line to a chart:

http://www.peltiertech.com/Excel/Cha...s.html#AddLine


Charles wrote:
I am producing a chart where column A contains days 1 - 365, column B has
values and CELL C1 has one value lets just say 20.
I want to chart whatever is in columns a and b (lets assume it is a line
chart) and want to draw a horizontal line in the chart at what CELL C1
contains.
Is this possible?


--
Debra Dalgleish
Excel FAQ, Tips & Book List
http://www.contextures.com/tiptech.html