I'm using Calibre to convert a PDF document to amazon paperwhite,
The issue I'm experiencing is that some of the sentences are split among multiple lines to the point where sometimes each word is on its own separate line.
I've tried MOBI, AZW3 formats but I keep getting the same result.
This is really the nature of the beast. PDF is a rendered format, so is MOBI. Converting from one rendered format to another is going to introduce these imperfections.
As I see it, you have two options: 1)convert the PDF to MS WORD (and fix all the formatting errors), then run it through Calibre and 2)read it only in a PDF reader on a mobile device.
Actually there is another option: use Amazon's Personal Docs/Content server (which will convert automatically from PDF to its mobi format). https://www.amazon.com/gp/help/customer/display.html/ref=hp_pdoc_main_short_us?nodeId=200767340 I have no idea whether Amazon's conversions are any better than Calibre; probably not, but it's worth a shot.
MS Word poses other conversion challenges, but at least it's something which can be processed more easily than PDF.
I read on another forum that the best way to improve PDF conversion was to enable the heuristic processing. Hope this helps https://www.reddit.com/r/ebooks/comments/1hst5i/converting_pdf_to_mobi_in_calibre_getting_a_gap/
No need of converting if you use k2pdfopt it'll resize pdf/djvu file to match to your screen size of paperwhite.
k2pdfopt <fileneamr.pdf> -dev kp3
For normal file. If you want to experiment with other options like number of columns or font size please follow the help of program. Its pretty good.
PDF actually sands for printable document format, that means the position on text are not relative but absolute and generally comes with A4 size. Now a page of A4 size might be shrinked(zoon out) while viewed on kindle against the very nature of re-flowing text in kindle.
Fortunately there a tool called K2pdf designed specifically to address this situation. Just use it to minimize the PDF size before you use Caliber and until caliber fixes this issue.
