Ebook Formats: What You Actually Need
The format landscape has simplified. Here's what matters in 2026:
Bottom line: Create a single high-quality EPUB. Upload it everywhere. Done.
#1. Vellum
Vellum produces the most beautiful ebooks in self-publishing. Chapter headings with ornamental styles, proper drop caps, device-optimized rendering, and typography that makes your book look like it came from a major publisher. Import a DOCX, choose a style, and Vellum generates separate EPUB files optimized for Kindle, Apple Books, Kobo, and generic readers.
The device-specific optimization is Vellum's secret weapon. Each retailer's reading app has quirks — different font rendering, spacing, and feature support. Vellum generates tailored files for each one, ensuring your ebook looks great everywhere instead of just acceptable.
Strengths
- Best ebook output quality, full stop
- Platform-specific EPUB optimization
- Gorgeous chapter heading styles
- Preview on simulated devices
Limitations
- Mac only — no Windows or browser version
- $200 minimum investment
- Limited customization beyond built-in styles
#2. Atticus
Atticus is the Vellum alternative for everyone who doesn't own a Mac. It runs in any web browser, handles both ebook and print formatting, and costs $50 less than Vellum. The ebook output is clean and professional — not quite Vellum's level of visual polish, but 95% of the way there.
The practical advantage of Atticus is flexibility. Write on your Chromebook, format on your iPad, preview on your desktop. One purchase, unlimited books, and active development keeps adding features. If you're not on a Mac, Atticus is the obvious choice.
#3. Calibre
Calibre is primarily an ebook library manager and format converter, but it includes a full EPUB editor. You can convert from practically any format (DOCX, HTML, TXT, RTF, ODT) to EPUB, then fine-tune the output. The conversion quality depends heavily on your source file — a clean, well-structured DOCX produces a clean EPUB.
The EPUB editor lets you work directly with the underlying HTML and CSS. If you know what you're doing, you can produce an ebook that's exactly how you want it. If you don't know HTML/CSS, the output will be functional but plain. Calibre is powerful, free, and ugly — in that order.
#4. Sigil
Sigil is a dedicated EPUB editor — not a converter like Calibre, but an editor that works directly with EPUB files. It has a split-pane interface showing code (HTML/CSS) on one side and a visual preview on the other. You can create an EPUB from scratch, import an existing one and fix issues, or validate your file against the EPUB spec.
This is a tool for people who are comfortable with HTML and CSS. If that's you, Sigil gives you total control over every aspect of your ebook. If HTML makes you nervous, use Atticus or Vellum instead — life's too short to debug CSS for chapter headings.
#5. Reedsy Book Editor
Reedsy's free editor produces clean EPUBs without any technical knowledge required. Write or import your manuscript, pick a formatting style, and export. The ebook output is straightforward — proper chapter breaks, table of contents, and clean typography. No decorative flourishes like Vellum, but no problems either.
Reedsy also offers collaboration features — you can invite beta readers or editors to work on your manuscript within the platform. For a free tool, it's remarkably polished.
#6. Kindle Create
Amazon's free tool produces well-formatted Kindle ebooks. Import your DOCX, apply a theme, and it generates a KPF file optimized for Kindle devices and apps. The themes are decent and the preview is accurate.
The fundamental problem: KPF is Amazon's proprietary format. You can't upload a KPF to Apple Books, Kobo, or your own website. If you're going Amazon-exclusive, Kindle Create works. If you plan to sell anywhere else — and you should — use a tool that outputs EPUB. You can still upload that EPUB to Amazon.
Selling Your Ebook Direct
Once you have your EPUB, you have a choice: give 30-65% to retailers, or sell directly to readers and keep almost everything.
Books.by lets you sell ebooks directly from your storefront. Upload your EPUB, set your price, and readers purchase and download instantly. You keep approximately 97% of revenue — no per-sale commission, just standard credit card processing fees (2.9% + $0.30). And you get the buyer's email address with every order.
The math is stark. A $9.99 ebook on Amazon pays you about $6.60 (70% royalty minus delivery fee). The same ebook sold direct on Books.by pays you about $9.50. Sell 100 copies direct and you've earned $950 vs $660 through Amazon — a $290 difference that more than covers your subscription.
Same EPUB, same price, same effort. $290 more in your account at 100 sales.
Sell Ebooks Direct. Keep 97%.
Books.by includes ebook hosting, delivery, and payment processing. Upload your EPUB and start selling today.
Get Started — Pro $299/year →Not ready for ebooks yet? Books.by also offers a print-only plan ($99/year) that covers print-on-demand with the same direct sales model. Add ebooks later by upgrading. See the full ebook formatting and distribution guide for the complete workflow.
Frequently Asked Questions
Vellum for Mac users ($200) — best output quality. Atticus for everyone else ($147) — works in any browser. Both produce professional EPUBs that work on all platforms.
EPUB. It's the universal standard. Amazon now accepts EPUB uploads (converts internally). Every other retailer uses EPUB natively. Create one good EPUB and it works everywhere.
Yes. Reedsy Book Editor (free, browser-based) is the easiest. Calibre (free, desktop) is the most powerful. Sigil (free, desktop) gives code-level control. All produce valid EPUB files.
Books.by handles ebook hosting, payment, and delivery. Upload your EPUB, set a price, and share your storefront link. You keep ~97% of revenue and get the buyer's email address.
