TEBookConverter is an easy-to-use ebook converter that uses calibre . Supported input formats are cbz, cbr, cbc, chm, djvu, docx, epub, fb2, html, htmlz, lit, lrf, mobi, odt, pdf, prc, pdb, pml, rb, rtf, snb, tcr, txt, txtz. Supported output formats are azw3, epub, fb2, oeb, lit, lrf, mobi, htmlz, pdb, pml, rb, pdf, rtf, snb, tcr, txt, txtz. You can convert ebooks fast thanks to multithreading.