Since you mention length only I will assume width is a constant......4 maybe?

Select A1 and DataValidationList

In the Source dialog enter 4,6,8,10,12,14,16 up to whatever.

Note these are comma-delimited.

In B1 enter =A1*4


Gord Dibben MS Excel MVP

On Fri, 11 Jul 2008 16:52:09 -0700, Razzamatazz
wrote:

I'm trying to get Excel to calculate different mathematical values based on
the user's selection from a drop-down list. The list contains various lengths
of drywall sheets and I want the program to calculate the square footage of
the sheets based on the one selected. Can't figure it out.