I've had the same problem, and it is annoying. It's counterintuitive that
these two different keystroke sequences (".5" and "50") result in the *same*
number when the cell is formatted as a percentage. The solution is to type
the leading zero. For instance, enter "0.5" instead of ".5" to get the
correct display of 0.5%.

"Abuzzmaster" wrote:

I have a spreadsheet I work with every day and I use fractional percentages,
between 0-1%. If the field is formatted as Percentage, and I type in ".5", it
reads it as 50%, which it would be if it weren't a percentage. But it is.
It's a half percent. By typing in "50", I also get 50%, which doesn't make
sense. If I type in "5" I get 5%, if I type in ".5", I should get .5%. Is
there a way to make this happen, or is this just a glitch in Excel? Please
help me figure this out. Thanks.