EPUB Editors: Digital Book Editing Software

Okay so I just spent like three hours yesterday testing Sigil again because someone in my publishing group said the new version finally fixed that annoying CSS bug and here’s what you actually need to know about EPUB editors.

Sigil Is Still Your Best Free Option

Look, I’ve tried probably every EPUB editor out there over the past seven years and Sigil keeps being the one I come back to when I don’t wanna pay for Vellum. It’s completely free, works on Windows, Mac, and Linux, and honestly does about 90% of what the paid options do.

The interface looks kinda dated but who cares. You can split your chapters, edit your CSS directly, preview how everything looks, and it has this plugin system that’s actually pretty useful once you figure it out. The learning curve is steeper than something like Calibre’s editor but way less steep than hand-coding everything in a text editor which I used to do like an idiot back in 2017.

Here’s the thing though – Sigil doesn’t hold your hand. You gotta know at least basic HTML and CSS or you’re gonna be lost. Not like expert level, just enough to understand what a div tag is and how to change font sizes in your stylesheet.

When You Should Just Pay for Vellum

Okay so this is gonna sound like I’m contradicting myself but if you’re on Mac and you’re publishing more than like two books a year, just get Vellum. It’s $249 for ebooks or $499 if you want print too and yeah that’s expensive but the time you save is insane.

I finally bought it in 2019 after fighting with Sigil formatting for my 50th book and I literally wanted to punch myself for not doing it sooner. You just paste your manuscript in, click the style you want, and boom – perfect EPUB and MOBI files in like ten minutes. The preview function actually works properly and shows you exactly what readers will see on different devices.

The main reason I still use other editors though is when I need to do weird custom stuff or fix problems in books other people formatted. Vellum doesn’t let you get into the code as easily which is sometimes what you need.

Calibre’s Editor Is Underrated

Wait I forgot to mention – Calibre has a built-in EPUB editor that most people don’t even know about because they just use Calibre for converting files. Right-click any EPUB in your Calibre library and choose “Edit book” and this whole editor opens up.

It’s honestly pretty powerful. You can edit the HTML files directly, mess with your CSS, check for errors, and it has this live preview that updates as you type. The interface makes more sense than Sigil if you ask me, everything’s organized better.

I use Calibre’s editor mostly for quick fixes – like when Amazon emails me saying there’s a formatting error in my book and I need to find it fast. The validation tools are really good at catching weird problems. Oh and another thing, it’s free and cross-platform just like Sigil.

The downside is it’s not really designed for creating EPUBs from scratch. Like you could do it but why would you. It’s more for editing existing files.

Finding and Fixing Common EPUB Problems

Both Sigil and Calibre have these validation checkers but they only catch technical errors not aesthetic ones. You gotta actually preview your books on different devices which is annoying but necessary.

I keep an old Kindle, a newer Kindle, and I test on my iPad with Apple Books. Different platforms render EPUBs differently and it’s frustrating as hell. Something that looks perfect in Sigil’s preview might have weird spacing issues on an actual Kindle.

The most common problems I see are broken table of contents, messed up chapter breaks, and images that are either too big or positioned wrong. Oh and fonts – people try to embed custom fonts and then wonder why half their readers see Times New Roman instead.

Jutoh If You Want Something In Between

This is gonna sound weird but Jutoh is actually really good even though nobody talks about it. It’s like $40 which is way cheaper than Vellum but more expensive than free options obviously.

Works on all platforms including Linux which matters if you’re one of those people. The interface is kinda cluttered and overwhelming at first but once you get used to it, you can format books pretty quickly. It generates EPUB, MOBI, and even PDF from the same project file which is handy.

I don’t use it much anymore because I have Vellum now but I recommended it to my friend who publishes on Windows and she loves it. The preview function isn’t as good as Vellum’s but it’s better than Sigil’s.

Reedsy Book Editor for Simple Projects

Okay so funny story – I was watching The Last of Us last month and formatting a simple poetry collection during commercial breaks and I used Reedsy’s online editor just because I didn’t feel like opening Vellum for such a short book.

Reedsy is completely free and web-based so you don’t install anything. You write or paste your content in, choose from their templates, and export to EPUB. It’s super limited compared to desktop editors but for straightforward books with no complex formatting it works fine.

The main advantage is it’s stupid simple. My mom could figure it out which is not something I can say about Sigil. But you can’t do custom CSS, you can’t really control the nitty-gritty details, and if something breaks you’re kinda stuck.

I use it maybe once every few months for rush projects or when I’m traveling and don’t have my main computer. That’s about it.

What About Google Docs and Word

People always ask me if they can just use Word or Google Docs and technically yes but also no. You can export to EPUB from both but the code they generate is usually a mess. Tons of unnecessary formatting tags, bloated file sizes, and weird spacing issues.

If you do go this route – which I don’t recommend but I get that budgets exist – you’ll need to clean up the EPUB afterwards in Sigil or Calibre anyway. So you’re not really saving time.

The only exception is if you’re using Draft2Digital or another aggregator that processes your Word file for you. They clean up the code before converting which helps. But for direct uploads to Amazon KDP I always use properly formatted EPUBs.

My Actual Workflow These Days

Since people ask – I write in Scrivener, export to Word, then import to Vellum for final formatting. If I notice any issues after uploading to KDP I fix them in Calibre’s editor because opening Vellum and re-exporting feels like overkill for small changes.

For my older books that weren’t formatted in Vellum I keep the source files in Sigil so I can update them when needed. This is actually important – always keep your source files organized because you’ll need to update books sometimes.

Like last year Amazon changed their formatting requirements slightly and I had to go back and fix the metadata in like 80 books. Having everything organized by editor type saved my sanity.

The CSS Thing You Gotta Understand

Real talk – if you’re gonna use EPUB editors seriously you need to learn basic CSS. Not web developer level but enough to change margins, line spacing, font sizes, that kind of stuff.

Every EPUB has a stylesheet that controls how text looks and if you don’t understand it you’re gonna struggle. The good news is CSS for ebooks is way simpler than CSS for websites. You only need like 20 properties max.

I learned from just googling “EPUB CSS examples” and copying code until I understood what did what. Took maybe a week of messing around. Now I can customize my books exactly how I want them which is huge for branding.

Sigil and Calibre both let you edit the CSS directly. Vellum generates it automatically but you can still tweak it if you export and open the file in another editor. Jutoh has a CSS editor built in too.

Plugins and Extensions Worth Using

Sigil has this whole plugin ecosystem that I ignored for like two years before finally exploring it. There’s plugins for generating tables of contents automatically, cleaning up code, checking for errors, all kinds of stuff.

The FlightCrew plugin is essential – it validates your EPUB against industry standards and catches errors that might make retailers reject your book. I run it on every book before uploading.

There’s also plugins for managing metadata, editing images, and even generating indexes if you’re doing non-fiction. You install them through Sigil’s plugin manager which is straightforward once you find it.

Calibre has plugins too but I use fewer of them. The Quality Check plugin is good for catching formatting inconsistencies.

Testing Your EPUBs Properly

This is where most people screw up – they format their book, it looks good on their computer, they upload it and then get bad reviews about formatting issues.

You gotta test on actual devices. The preview in KDP is better than it used to be but it’s still not perfect. I always download my book after publishing and check it on real Kindles and in Apple Books.

There’s also online EPUB validators like the one from IDPF that check if your file meets technical specifications. Run your EPUB through one before uploading to catch any code problems.

My cat just knocked over my coffee which is annoying but anyway – the point is testing takes time but it’s worth it. A badly formatted book gets returned and gets bad reviews which tanks your sales.

When to Hire Someone Instead

Look, if you’ve tried all this and you’re still struggling, sometimes it makes sense to just hire a formatter. You can find decent ones on Fiverr or Reedsy for like $50-150 per book depending on complexity.

I still do all my own formatting because I’m cheap and I like controlling every detail but I have author friends who outsource it and they’re happy. The time they save goes into writing more books which probably makes more financial sense honestly.

Just make sure whoever you hire gives you the source files so you can make updates yourself later. Don’t be dependent on them for every tiny change.

The main thing is figuring out what works for your situation and budget. There’s no one right answer which I know is annoying but it’s true. I’ve published over 200 books using like five different tools depending on what made sense at the time.

Start with the free options, learn the basics, then upgrade if you need to. That’s the path that worked for me and most successful self-publishers I know.