Sigil review

Sigil is a dedicated EPUB editor maintained by volunteers, and it remains completely free to download and use. It supports both EPUB 2 and EPUB 3 and gives you two ways to work: Code View for editing the markup directly and Preview View for checking the result. A table of contents generator handles multi-level headings, a metadata editor fills in title and author details, and spell checking accepts custom dictionaries. Power users get full regular expression find and replace, plugin support and checkpoints that compare snapshots of your changes. The developers describe it as suited to anyone from authors formatting their own books to professional editors publishing on several platforms. In practice, Sigil rewards people who know HTML and CSS. There are no design themes, no print output and no Kindle-specific files, so most authors pair it with a formatter such as Reedsy Studio or Atticus and use Sigil to polish or repair the final EPUB.

Who it is for

Professional editors and detail-minded authors who want full control over EPUB code at no cost.

Price

Free and open source under GPLv3.

Sigil was originally created by Strahinja Markovic in 2009 and remains completely free to download and use.
Quoted from the vendor pricing page on November 11, 2026.

Key features

• EPUB 2 and EPUB 3 spec support
• Code View for direct EPUB editing and Preview View
• Table of Contents generator with multi-level headings
• Metadata editor and spell checking with custom dictionaries
• Regular expression find and replace, plugins and checkpoints

Strengths and weaknesses

• Strength: Free and open source software under GPLv3
• Strength: Runs on Windows, Mac and Linux
• Strength: Complete control over EPUB markup for precise fixes
• Weakness: Assumes comfort with HTML and CSS
• Weakness: No guided themes or print output
• Weakness: Edits EPUB only, so Kindle files come from other tools

Key facts

• Price: Free, GPLv3
• Platforms: Windows, Mac, Linux
• Format: EPUB 2 and EPUB 3
• Maintainers: Volunteer team led by Doug Massay and Kevin Hendricks

Where it ranks

Sigil is No. 7 in our Best Ebook Creation Software verdict.