HTM to EPUB

How to do it

1. Download Asteria and open it. It's free and needs no account.
2. Drop your HTM files onto its window, or press ⌘O (Ctrl O on Windows) to choose them. Drop as many as you like.
3. Type convert to epuband press Enter. EPUB e-book from Markdown, HTML or Word.
4. The first time, Asteria asks to download Pandoc, a free add-on from John MacFarlane, under the GPL-2.0-or-later license. It shows the download size before you say yes, and needs no administrator password.
5. Press ⌘↵ (Ctrl ↵ on Windows) to save. The EPUB files appear next to the originals, which stay exactly as they were.

What it needs

HTM to EPUB uses Pandoc, a free program for Markdown, LaTeX and web documents. Asteria doesn't bundle it. The first time you need it, Asteria offers to download it, checks the download against a pinned checksum, and keeps it in its own folder, where Settings can remove it again. If Pandoc is already on your computer, Asteria uses that copy.

How it was tested

A real HTM file was converted on macOS on Apple silicon and Linux, and the EPUB that came out was opened and checked with zip package + XML text to make sure it is what it says it is.