Top Alternatives to calibre

Okular is a versatile document viewer from the KDE community, supporting a wide array of file formats including PDF, EPUB, DjVu, and TIFF. It offers intuitive navigation, robust annotation tools, and features like text selection and saving, making it a powerful tool for handling diverse document types.

Google Play Books is a comprehensive digital library and ereader offered by Google. It provides access to a vast collection of ebooks and audiobooks for purchase or free download, allowing users to read and listen seamlessly across multiple devices with offline capabilities.

Apple Books (formerly iBooks) is Apple's native e-book and audiobook application for iOS and macOS devices, providing a seamless reading and listening experience with robust library management and sync features.

Polar is a powerful desktop application designed to serve as an integrated reading environment. It allows users to actively read, annotate PDFs and web pages, create flashcards for spaced repetition learning, organize their digital library, and track their reading and learning progress. It's built for focused and deep engagement with digital content.

Delicious Library is a comprehensive digital asset management application for macOS, allowing users to effortlessly catalog and organize their collections of books, movies, music, and video games by scanning barcodes with a webcam or external scanner.

Cool Reader is a highly configurable and lightweight eBook viewer designed for comfortable reading on various devices. It supports multiple formats including EPUB and DOCBOOK, offers extensive customization options for interface and reading experience, and includes useful features like library management, annotations, and sync capabilities.

Aldiko is a versatile e-book reader for Android and iOS, supporting a wide range of formats including EPUB and PDF. It offers a rich reading experience with customizable settings, library management, annotation tools, and synchronization options.

Moon+ Reader is a highly customizable and feature-rich ebook reader for Android devices, supporting a wide range of ebook formats and offering advanced options for reading comfort and library management.

EPUBReader is a lightweight and efficient browser extension that allows users to open and read EPUB e-books directly within their web browser. It provides a simple and intuitive reading experience without requiring external software.

AlReader is a highly customizable and feature-rich e-book reader application designed for mobile devices. It supports a wide range of formats, offers extensive configuration options for reading interface, and includes features like text-to-speech, library management, and synchronization.

ICE Book Reader Professional is a highly customizable e-book reader and teleprompter with a focus on performance and comfort. It supports a wide range of formats and offers advanced features for managing and reading your digital library.

Albite READER is a free ebook reader for Java-enabled mobile phones, providing a customizable reading experience with offline access to your digital library. It supports various ebook formats and includes features like night mode, bookmarks, and library management for a convenient reading experience on older mobile devices.

Document Viewer is a highly customizable and lightweight document viewer designed for Android devices. It supports a wide range of formats including PDF, DjVu, XPS, CBZ, CBR, and ePub, offering features like highlighting, annotation, and optimal performance.