EDIT: the site is unfortunately no longer online
If you are a fan of e-readers and ebooks, you are probably aware that there are several file formats for e-books. Unfortunately, not all e-readers are capable of reading all formats and it can sometimes be useful to convert an ebook to PDF so that you can read it on any device.
So it's not uncommon to have to convert ebooks into a format other than the one you have on hand.
There are many software programs that you can install to do the job on your computer, such as the go-to Calibre, but sometimes it's nice to be able to skip the software altogether and use a free online service that doesn't require installation. This is the case, for example, withOnline eBook Converter, a free and fairly comprehensive tool.
Indeed, this tool allows you to convert a large number of formats (ePub, PDF, Mobi, unprotected AZW, unprotected TOPAZ, unprotected PRC, unprotected TPZ, HTML, TXT, LIT, LRF, FB2, PDB, etc.) to 3 relatively universal formats: ePub, Mobi and PDF.
Convert an ebook
Step 1: Choose a format to convert your ebook to (ePub, Mobi or PDF)
Step 2: Upload your ebook (not protected by DRM – digital rights). To do this, click on “Browse Files” and locate on your computer the file(s) you want to convert.
Step 3: Download your converted ebook. Once your ebook is converted, you will have a download link for each of the books you uploaded.
Obviously no miracles, Online eBook Converter does not allow you to convert protected ebooks such as Amazon's proprietary formats (AZW, AZW3, AZW4, etc.). In these cases, you will need to turn to other software published in particular by ePubor, the company that provides this free tool.
Online eBook Converter
great article, it really helps