Guide

How It Works

The app uses Calibre's ebook-convert command-line tool behind the scenes. When a visitor uploads a supported file, the application validates the extension, checks that the requested output format is allowed for that source type, and runs the conversion process on the server.

Format rules

• PDF uploads can be converted to AZW3, MOBI, or EPUB.
• EPUB, AZW3, and MOBI uploads can be converted to PDF.

Why output can vary

Ebook conversion is not always lossless. PDFs are fixed-layout documents while EPUB and Kindle formats are typically reflowable. Complex tables, scanned pages, annotations, unusual fonts, or embedded graphics may not survive perfectly across formats.

Practical advice

Use clean source files, verify the output manually, and keep the original file if the conversion is intended for business, academic, legal, or publishing use.