“created at” or “created in”

Question

I'm making a program and I need to label a "creation date" field. I'm not sure whether to write

Created in __

or

Created at __

Answer 1

On for days and dates, in for duration, at for precise times, including full dates that include the time:

Created in 3 hours and 15 minutes.

Created on the 13th of July

Created on 2013-07-13

Created at 14:35

Created at 2013-07-13 14:35

Created at 2013-07-13T14:35:00Z (when ISO dates are appropriate).