How To Change The Font Size Of PDF File In Kindle E-Readers Posted on by Webmaster IT Support Forum › Forums › Other Technology › How To Change The Font Size Of PDF File In Kindle E-Readers Tagged: Calibre, Font Size, Kindle, PDF This topic has 0 replies, 1 voice, and was last updated 9 years, 4 months ago by Webmaster. Viewing 0 reply threads Author Posts July 21, 2014 at 9:41 pm #516 WebmasterKeymaster Want to change the font size of PDF files in Kindle? Here’s how to change font size in any version of kindle: Download and install Calibre Use Calibre to convert the PDF file into a .mobi file Copy the .mobi file to your Kindle You will now be able to change the font size on your Kindle. Author Posts Viewing 0 reply threads You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In