Fonts in an ebook, and why yours may not be used
This is the mismatch that produces more disappointed authors than any other part of an ebook. You spend a week choosing a body face for the print edition, get it right, then open the EPUB on a phone and find the book set in something else.
Nothing is broken. The two formats hand the same decision to different people.
In print, you are the typographer. You pick the face, the size, the leading and the measure, ink goes onto paper, and every copy is identical forever. In an ebook the reader is the typographer. Face, size, line spacing, margins, background color and justification are all controls on the device, and the file's typography is a request, not an instruction.
The reader chooses, and has reasons
Most reading systems let a reader set a preferred font and apply it to everything they read, and plenty do that once and never revisit it. Behavior varies by app, by device and by version, and it changes — check your own targets rather than trusting any list, including this one.
What does not vary is why they do it. A reader who has set a particular face at a particular size has usually done it because that combination is the one they can read comfortably for two hours: larger type for tiring eyes, open shapes and unambiguous letterforms for a reader with dyslexia, more line spacing to stop lines from swimming. Those are the accommodations that justify the large print edition most authors never make in paper, except here the reader makes them for themselves. Overriding that is not a design win.
So: your typographic choices in an ebook are defaults. Good defaults matter. But a book whose identity depends on its body typeface has no identity on half the devices it will be read on.
Embedding is permitted, and it is not a guarantee
An EPUB can carry font files inside it and ask for them in its stylesheet. That is a standard part of the format, and it works — sometimes.
The things that get in the way are outside your control. A reading system may offer the reader a switch that turns publisher fonts off, and the reader may have left it off. Some disregard embedded fonts for body text entirely; some honor them for headings and not for running text. A conversion step between your EPUB and the file a store delivers may not carry every face through. All of it varies enough that the only reliable statement is the general one: embedding raises the chance your face is seen and does not make it certain.
Which means you never build anything load-bearing on top of it. If a chapter opening only reads as a chapter opening because of the face it is set in, it will fail silently for some readers, and you will not hear about it.
In the Interior Formatter. It builds the EPUB 3 and the print PDF from one structured source, so the print edition gets its real body face — Crimson Text, Gentium Book Plus, Spectral, EB Garamond, Lora or Alegreya — while the ebook carries the structure that survives whatever the reader picks: chapter starts, scene breaks, emphasis, accessibility metadata, a declared language and ARIA roles. Start your ebook → · about the Interior Formatter
Where embedding genuinely earns its place
Three cases, and outside them the cost is usually not worth paying.
A display face for chapter headings. Headings are short, seen as shapes rather than read as text, and the likeliest part of a book to be honored by a system that ignores body fonts. One face, at one or two sizes, for chapter and part titles. If it fails to load the heading is still a heading — marked up as one, in the navigation, announced by a screen reader — so the book degrades into something plainer rather than something broken.
A face carrying characters the defaults lack. The strongest case, because it is about the text being legible at all rather than about taste. Transliteration with combining diacritics, Greek or Cyrillic passages, phonetic symbols, extended mathematics, a constructed script for your fantasy world. A default font missing a character shows a substitute glyph or an empty box, and a reader cannot guess what was meant. Accents, symbols and characters that go missing covers the same failure in print.
Fixed layout, where the layout is the point. A picture book, a comic, a cookbook whose spreads are designed objects. The page is frozen by definition and the type is part of the artwork, so the fonts come with it — a different format with a different set of trade-offs: Fixed layout: when the page is the design.
The licensing point authors miss
Putting a font inside an EPUB is not using the font. It is redistributing it: a copy of the software goes out with every file you sell, and anyone who can open the archive can take it out.
Font licenses treat that as a separate right, and many do not grant it. A desktop license typically covers making documents on your own machine and stops there; embedding is often sold as its own tier, sometimes metered, sometimes capped by copies. The license decides, not the format, and reading it is the whole job — the same discipline as Stock images: what the license actually lets you do.
This is why openly licensed families are the practical answer. Free font libraries carry faces whose licenses permit embedding and redistribution outright, several of them serious book faces with full character sets, and using one removes the question rather than answering it. If you do embed a commercial face, keep the license file with the book so a future you can prove what was allowed.
Every face you embed adds weight
A font file is not small, and a family is several files — regular, italic, bold, bold italic, each a separate face. Embed a full family and you add a meaningful fraction to a novel whose text is a fraction of a megabyte.
That matters because some stores meter file size against what they pay you, and the rules differ by store and change over time. Look up the current terms wherever you publish. Meanwhile: subset if your tool can, embed only the weights you use, and never embed a face for a paragraph or two. Why your ebook is enormous, and what to do is the full accounting.
What we do, and why
Our EPUB 3 output asks for a generic serif and stops there. It validates with zero errors and zero warnings under epubcheck, and it carries accessibility metadata, a declared language, ARIA roles and chapter numbering.
Asking for a generic serif is a decision, not an omission. The book opens in whatever serif the reader's system provides — on a device they chose, configured and read on every night, that is a face which already works for them — and the moment they change it, nothing about your book resists. The print edition is where the typeface is yours. The ebook is where the reader's choice wins, and building for that is the difference between a book that reads well everywhere and one that reads well on your screen.
Make your ebook
The tools are free to use: bring your manuscript once and get both a print PDF and an EPUB out of the same source, so the two editions cannot drift apart. You only pay when you want the files without the preview watermark.
Next: How your ebook actually looks on other people's devices · More: Reflowable text, and the things that break it · Why your ebook is enormous, and what to do · Choosing a typeface for the body of a book