Change the number of decimal places to 3 or 4, or even leave it as "Auto". When you set it to a specific number of places, Access just formats the value to show that number of places so it looks rounded.

Donald. Thanks for the assist. Auto did not work, but "4" did work.

Kirk   You need to type the leading zero in order for Access to process the percentage properly.  If your field is formatted as percentage, then:

If you type 0.125, Access will enter 0.125% (with the underlying value 0.00125, as it should be).  This is the way it's supposed to work.  You don't need to type 0.00125 just to get 0.125%.

But if you type .125 instead, Access will enter 12.5% instead.  This is due to a still-unfixed quirk of Access, covered in this video by Richard:

     https://www.youtube.com/watch?v=1NnW-5yKfxE

Thanks Kevin.  I do that. It actually makes some sense mathematically.  Typing the two zeros is the placeholder for tens and ones. I caught on to that one rather quickly. Thanks for the assist.

Update.  The problems continued with Access rounding.  I kept experimenting with the issue and I have found a solution that is stable.  with my field parameters set at Double, percent, 4;  If I want to have ".13" in a field, I enter "0.13"  Entering the "0" and the "." first works and Access does not round.  Importantly, the correct value is visible in the field for tables, queries, and forms.

Kevin, you were right. Thanks again.