9 articles in this topic.
If you are an avid reader or self-published author, the biggest hurdle is often format compatibility. The short answer is: **Kindle users should use AZW3**, while **Kobo and other e-readers prefer EPUB**. MOBI is outdated for new devices. Use tools like [bookconv.com](/convert) or Calibre to convert your files instantly. For the head-to-head of the two formats themselves, see our [EPUB vs MOBI comparison](/blog/epub-vs-mobi).
Navigating the world of e-readers can be a maze of acronyms and incompatible formats. Whether you are a self-published author preparing a manuscript for launch or an avid reader trying to sideload your favorite library books, the question remains: which format actually works best for your device? This guide breaks down the compatibility of AZW3, EPUB, and MOBI for Kindle and Kobo devices, helping you choose the right format and convert your files effortlessly using free tools like BookConv.
Turning a physical manuscript or a complex document into a polished ebook is one of the most critical steps in modern publishing. Whether you are a self-publishing author preparing your debut novel for Kindle, a digital archivist preserving rare texts, or a librarian managing a growing ebook collection, the quality of your conversion determines whether readers enjoy your work or give up in frustration. While free tools like Calibre are excellent for basic format swapping, they often fall short when dealing with complex layouts, images, or scanned physical books. In this guide, we explore the best tools and methods for converting various file formats into ebooks, comparing open-source software with professional services like BookConv to help you choose the right path for your specific needs.
Choosing the right eBook format is the single most critical step in self-publishing or digital distribution. If you are reading on a Kindle Paperwhite, you need AZW3 for the best experience; if you use a Kobo Clara or Nook, EPUB is the gold standard. Many authors and readers still struggle with the transition from the legacy MOBI format, which Amazon has largely deprecated in favor of more feature-rich containers. At BookConv, we see countless creators losing formatting fidelity by uploading uncompressed files to conversion tools. This guide explains exactly which formats your device supports, why AZW3 beats MOBI for Kindle users, and how to convert your manuscripts for free without ruining typography, footnotes, or metadata. For the direct EPUB vs MOBI decision, see our [full comparison guide](/blog/epub-vs-mobi).
Reading across multiple devices is convenient until your progress stops syncing. This guide explains how Kindle, Kobo, and Apple Books each handle sync, which format to choose, and how BookConv's free, browser-based converter helps you prep files for seamless cross-device reading — no software to install.
If you just bought a Kobo and you have a shelf of old MOBI files, the first question is simple: will they even open? The short answer is that Kobo's native, best-supported format is EPUB, not MOBI. MOBI is Amazon's legacy format, and while some Kobo firmware will limp through a MOBI sideload, the clean result everyone wants comes from converting MOBI to EPUB first. This guide shows you the fast, no-install way to do it and get your books onto your Kobo.
You do not need to pay to read ebooks well. Every major platform has a free, capable reader app, and the right one depends on your device and your format. Here is the practical shortlist of free ebook reader apps for 2026, organized by where you read.
Kobo's own format is already EPUB under the hood (its tuned variant is called KEPUB), so "converting a Kobo book to EPUB" is often simpler than it sounds — or impossible, if the book is store-DRMed. This guide explains both cases and what you can actually do.
Sitting on a pile of old .mobi files that only open on a Kindle? MOBI is Amazon's legacy format, and most non-Kindle readers — Kobo, Apple Books, Google Play Books — won't touch it. Converting MOBI to EPUB frees your books to read anywhere, because EPUB is the open standard nearly every device supports. This guide covers the quick conversion and what actually moves across. New to the format question? Our [EPUB vs MOBI explainer](/blog/epub-vs-mobi) covers which to keep as your master file.