Amazon's KDP suggests an aspect ratio of 1.6 for ebook covers. I just read that publishers use a 1.5 ratio.
One site I found had the following:
An aspect ratio of 1.5 may have some merit:
- It's not as narrow as Amazon's recommendation.
- It provides a little more width for the title.
- It matches the aspect ratio of the fairly popular 6″ x 9″ book (which is convenient if you publish a paperback of this size at CreateSpace, for example).
- It will only be a little wider than the multitude of covers that follow Amazon's recommendation, so it probably isn't wide enough to seem out of place.
What do you all think?