In xl2003:
tools|Options|Edit tab
check Enable automatic percent entry

Or type
20%
(include the % sign)

wrote:

Hello, I am having a tough time getting a document to display
percentages correctly. For example, I want a percentage to show up as
"20%" but for whatever reason, when I type in "20" into the cell it
automatically kicks back 2000%. I have cleared formats several times,
and have my format set on "Percentage, 0 decimal places." Any idea
what I am doing wrong?

--

Dave Peterson