Free Alternative to Kindle

Calibre is the gold standard for ebook management—completely free and open source with over 15 years of active development and a community of millions of users worldwide. It functions as a complete ebook workstation: organize your library with sophisticated metadata management, convert between formats with professional-grade quality, edit ebooks directly with integrated HTML/CSS tools, fetch news from 1,500+ sources automatically converted to ebooks, and sync with any e-reader hardware. Unlike Kindle, Calibre stores your books as files you control on your local system with no cloud dependency or corporate oversight.

It supports virtually every ebook format including EPUB, MOBI, AZW3, PDF, DOCX, ODT, RTF, TXT, HTML, LIT, PDB, and dozens more, with lossless conversion that preserves formatting, metadata, and cover art. The integrated ebook viewer handles all supported formats with customizable reading options including adjustable fonts, color schemes, page layouts, and reading statistics. Calibre's content server turns your library into a private streaming service accessible from any device on your network via web browser, complete with OPDS catalog support for integration with mobile readers.

The plugin system extends functionality with over 300 community-developed extensions for everything from advanced DRM handling to Goodreads integration to custom metadata sources. Batch operations allow you to edit metadata, convert formats, or update covers for thousands of books simultaneously using search and replace with regex support.

Apple Books delivers a polished, native reading experience that rivals Kindle's interface quality while respecting user privacy far better than Amazon's ecosystem. With one major advantage over Kindle: access to over 30,000 free public domain titles directly from Project Gutenberg integrated into the store interface, requiring zero additional setup or external sources. The app syncs seamlessly across all your Apple devices via iCloud, automatically remembering your reading position down to the exact word, syncing highlights and notes bidirectionally, and backing up your entire library without user intervention.

While it also sells contemporary titles, the free classics library means you can read Shakespeare, Austen, Dickens, Tolstoy, and thousands more literary masterpieces without spending a cent. The interface is clean, intuitive, and beautifully designed with smooth page turns powered by Core Animation, excellent night mode implementation with true black for OLED screens, and gorgeous typography using professionally selected fonts including Times New Roman, Athelas, Charter, Georgia, Iowan, Palatino, San Francisco, Seravek, and any custom fonts you install. Apple Books integrates deeply with macOS and iOS, supporting features like Handoff (continue reading on another device instantly), Siri reading aloud, system-wide text selection and lookup, and OverDrive/Libby for borrowing from your local public library directly within the app.

Foliate is a modern, GTK-based ebook reader designed specifically for Linux with over 100,000 downloads and growing adoption across distributions. It emphasizes a clean, distraction-free reading experience with beautiful typography inspired by Apple Books and smooth hardware-accelerated animations that feel native to GNOME and other GTK-based desktop environments. Version 3.0 brought a complete GTK 4 rewrite with hardware-accelerated page transitions using OpenGL that feel like turning real pages, adaptive layout that works beautifully on phones and tablets via Librem and PinePhone, and improved performance with reduced memory usage.

It supports EPUB, MOBI, Kindle AZW/AZW3, FictionBook FB2/FB2.ZIP, comic books (CBZ/CBR), and more, with excellent rendering quality using WebKit2GTK for maximum compatibility. The built-in OPDS integration lets you discover and download free ebooks directly from Project Gutenberg, Standard Ebooks, Feedbooks, and other catalogs without leaving the app, with full catalog browsing, search, and one-click downloads.

KOReader is an open-source document viewer meticulously optimized for e-ink devices like Kindle, Kobo, PocketBook, reMarkable, Onyx Boox, and over 20 other models, bringing true format freedom to locked-down hardware. It unlocks capabilities Amazon intentionally restricts—install it on a Kindle and suddenly you can read EPUB files natively without conversion, customize every aspect of the UI down to sub-pixel font rendering and gamma curves, and enjoy superior PDF handling that rivals dedicated PDF readers costing hundreds of dollars. The PDF reflow feature is genuinely exceptional for academic papers and scanned documents on small screens, using intelligent algorithms to detect columns, headers, footers, and figures, then reformatting text for optimal readability while preserving logical flow.

It syncs reading progress, bookmarks, and highlights across all your devices via KOReader Cloud (self-hostable) or third-party services like Dropbox, ensuring you never lose your place. The statistics tracking is comprehensive, logging reading speed, time spent per book, and completion percentages with beautiful charts. Integration with Calibre's wireless connection allows seamless library management without USB cables.

Librera Reader (previously known as Lirbi Reader and PRO Reader) is a free, open-source ebook reader for Android that supports virtually every format imaginable—PDF, EPUB, EPUB3, MOBI, DJVU, FB2, FB2.ZIP, TXT, RTF, AZW, AZW3, HTML, CBZ, CBR, DOC, DOCX, and over 20 others, making it the most format-flexible reader available on any platform. With more than 17 million downloads across the Google Play Store and F-Droid, it has proven itself as a lightweight yet powerful alternative to Kindle that respects user freedom. Librera is significantly lighter and more responsive than the bloated Kindle app while offering genuinely advanced features like Bionic Reading mode that highlights word prefixes for improved focus and reading speed (proven effective for ADHD readers), configurable text-to-speech with MP3 export for creating audiobooks from any text, and a musician's mode with auto-scrolling at precise speeds perfect for reading sheet music during performance. The interface is highly customizable with themes ranging from minimalist to feature-rich, custom font support including Google Fonts integration, and gesture controls tailored to your reading preferences and hand size.

Sumatra PDF is a free, open-source document viewer for Windows that's incredibly lightweight, fast, and focused on doing one thing exceptionally well—displaying documents instantly without bloat. The entire application is under 10MB (compared to Adobe Reader's 300+ MB) and launches in under a second, making it perfect for quick document viewing without the bloat, slow startup, or security vulnerabilities of Adobe Reader. While primarily known for exceptional PDF support including XFA forms and JavaScript, it also handles ebook formats including EPUB, MOBI, FB2, CHM (Windows help files), and comic books (CBZ/CBR with RAR support).

It's designed with minimalism in mind following the Unix philosophy—no unnecessary features, complex menus, or feature creep, just fast, reliable document viewing with essential reading tools like bookmarks, table of contents navigation, and customizable keyboard shortcuts for power users. The portable version requires no installation and can run from a USB drive, making it ideal for IT professionals and users who need document access on locked-down systems.

FBReader (FavouriteBook Reader) is one of the oldest and most popular ebook readers with over 50 million downloads across Windows, macOS, Linux, Android, and iOS platforms since its initial release in 2005. It pioneered many features now standard in ebook readers and continues active development with regular updates. FBReader supports major ebook formats including EPUB, MOBI, FB2 (FictionBook), HTML, RTF, and plain text, with excellent rendering quality and customization options. Cloud synchronization for reading positions, bookmarks, collections, and preferences works across all platforms via FBReader's proprietary sync service, allowing you to seamlessly switch between your phone, tablet, and computer while maintaining your reading progress and library organization. The interface is clean, customizable, and designed for distraction-free reading with extensive options for fonts, colors, page layouts, and reading modes. FBReader's network library catalog provides access to thousands of free ebooks from various sources including Project Gutenberg, Feedbooks, and OPDS catalogs, with integrated browsing, search, and downloading.

Thorium Reader is a free, open-source ebook reader specifically designed with accessibility in mind, developed by the EDRLab (European Digital Reading Lab) consortium of publishers, libraries, and accessibility organizations. It provides exceptional support for screen readers like NVDA, JAWS, and VoiceOver, full keyboard navigation throughout the entire interface, and extensive visual adjustments for users with dyslexia, low vision, color blindness, and other reading disabilities. It's fully compliant with EPUB Accessibility 1.0 standards and WCAG 2.1 Level AA guidelines, supporting DRM-free EPUB and PDF files with tagged PDF support for accessibility.

The interface is clean, modern, and built with Electron for cross-platform compatibility across Windows, macOS, and Linux with native performance. Thorium includes features specifically designed for users with disabilities: reflow and customization options that go far beyond typical readers, high-contrast modes, spacing adjustments to reduce visual crowding, and specialized dyslexia-friendly fonts. Unlike commercial readers that treat accessibility as an afterthought, Thorium was designed from the ground up with disabled readers as the primary audience.

Moon+ Reader is one of Android's most popular and feature-rich ebook readers with over 30 million downloads and a dedicated user base that considers it the best reading app on any platform. It supports an incredibly comprehensive range of formats including EPUB, PDF, DJVU, AZW3, MOBI, FB2, PRC, CHM, CBZ, CBR, UMD, DOCX, ODT, RTF, TXT, HTML, WEBP, and even compressed archives like RAR and ZIP. What sets Moon+ Reader apart is its obsessive attention to customization and control—24 customizable operations across screen clicks, swipe gestures, and hardware keys can trigger 15+ events including search, bookmarks, themes, navigation, font adjustments, and more.

The visual customization is unmatched with 10+ built-in themes, day/night auto-switching, line spacing adjustment, font scaling, bold and italic formatting, text shadows, justified alignment, alpha color controls, and fading page edges. Auto-scrolling with adjustable speeds makes it perfect for hands-free reading during meals or exercise. The backup and restore system syncs reading positions between phones and tablets via Dropbox, ensuring continuity across devices. Annotation capabilities are professional-grade with highlighting in multiple colors, margin notes, bookmarks with labels, dictionary lookup (supporting ColorDict, GoldenDict, Fora, ABBYY Lingvo), and translation features.

PocketBook Reader is the official companion app for PocketBook e-readers, but it works as a standalone reading app on iOS, Android, Windows, and macOS with impressive capabilities. It supports an industry-leading 26 book and audio formats including EPUB, MOBI, FB2, PDF, DJVU, DOCX, RTF, TXT, HTML, CBZ, CBR, and even audiobook formats like MP3 and M4B, making it one of the most format-comprehensive readers available. The free PocketBook Cloud service synchronizes your entire library including books, audiobooks, reading positions, notes, bookmarks, and collections across all devices automatically with 2GB of free cloud storage (expandable to 50GB).

Integration with Dropbox and Google Drive allows you to access books stored in your existing cloud storage without importing them locally. The PDF reflow function intelligently reformats PDF documents for small screens by detecting text blocks and reflowing them, making it possible to read scanned documents and academic papers comfortably on phones. Text-to-speech engine built into the app can voice any text file in multiple languages with adjustable speed and pitch.

The reading interface offers extensive customization including adjustable fonts, text size, line spacing, margins, page-turn effects, and themes. Unlike many readers, PocketBook is completely ad-free even in the free version.

Book's Story is a new, modern open-source ebook reader for Android built with Material You design principles and a focus on privacy, simplicity, and user experience. Unlike older readers with cluttered interfaces, Book's Story provides a clean, intuitive experience that feels native to modern Android with dynamic color theming that adapts to your wallpaper. It supports EPUB, FB2, TXT, HTML, and PDF formats with excellent rendering quality using web technologies for maximum compatibility.

The app is completely free with no ads, no tracking, no account requirements, and no premium upsells—genuine free and open source licensed under GPLv3. Reading customization includes adjustable fonts, line spacing, paragraph spacing, margins, text alignment, and hyphenation with multiple color themes. The app includes a built-in translator for reading books in foreign languages with on-demand translation of selected text.

Library management features include collections, search, sorting, and metadata editing with automatic cover downloads. Despite being newer and less known than established readers, Book's Story has gained popularity among privacy-conscious users who want a modern reading experience without corporate data collection.