PDF initilally was one of the most common eBook format. However, the use of Adobe PDF files isn't very comfortable with the most of existing eBook readers. For better reading experience on different eReaders we're often in the need to convert a PDF files to more conventional and resource-friendly formats such as .epub or .mobi (for Kindle reading devices).
eReading on iPad
If you're an iPad owner, the situation become even more complicated. After exploring the eReading features of your tablet, you'll for sure find that there is no PDF support for your existing eBooks. Don't panic! Everything is doable - you can drag any new ePub file over to your iPad and it will appear in the reader app. However, you indeed need to convert all your old PDF books. Luckily there is already a free cross-platformed software to do it quick, easy and for free: the Caliber eBook.Free online eBook Converters to download
The Caliber eBook lets you convert PDF, .doc and other types of eBook files to the needed format supported by this or that eReader or app. Usually, the input formats could be .pdf, .doc, .docx, .epub, .mobi, .azw, .fb2, .html, .lit, .lrf, .odt, .pdb, .prc, .rtf, .txt.