Often the product description will not only give you the size of the file but
the estimated page length.
Not exact matches
This excerpt from
pages 24 and 25 of Book Design Made Simple should help you
estimate the
length of your front and back matter.
Estimated length is 350
pages.
The marvellously titled Kindle Edition Normalized
Page Count (KENPC) appears to have been set so a novel can work out at nearly twice the
length of the
estimated «Print
length» included in Kindle book details.
For example, Charlotte's Wedding by Mary Rizza has an
estimated «Print
length» of 221
pages in its Kindle details, but has a KENPC of 409
pages — an 85 % increase from the print to ebook version.
All books have an
estimated length of 336
pages.