iloveepubProcessed locally — files never leave your device
Merge EPUB
Combine multiple EPUB books into one file with a unified table of contents — entirely in your browser. Free, no upload, no limits.
01Add your EPUB files
02Name the merged book
Used as the title in the merged book's metadata and table of contents.
03Merge & download
When one file is what you actually need
A trilogy you want as a single Send to Kindle item, a course packet of lecture EPUBs, or three public-domain volumes that should occupy one slot on a Kobo shelf. Merging is a reading-order problem, not a conversion. You already have valid books. You want one package, one title, and a table of contents that shows where each book starts.
It is the wrong tool when the sources are scans you still need to shrink, or when one of them will not open. Compress or Fix My EPUB first. A merged file is at least as large as the sum of its parts, and Send to Kindle email still stops at 50 MB.
What gets written into the new EPUB
Each input is unpacked on its own, then released, so a phone is not asked to hold every book at once. Files are copied under OEBPS/book-1/, OEBPS/book-2/, and so on. Manifest ids are rewritten so the books cannot collide. The original navigation documents are not copied, because their links point at the old paths. A new nav.xhtml and a new toc.ncx are written instead. Each source title is a top-level entry, and that book's chapters sit underneath it.
A new content.opf carries the title you typed and a spine in the order you arranged. The mimetype entry is stored first, uncompressed. Markup is deflated. Images, fonts, and audio are stored, not recompressed. Relative links inside a source book keep working, because that book stays a folder and its relative URLs are unchanged. Reading position and highlights never move: those live in the reader app, not in the EPUB.
Limits that are real
You need at least two EPUB files. Each input is capped at 80 MB so the tab is less likely to be killed mid-copy. There is no fixed count of books beyond that memory ceiling. DRM files are rejected. The tool does not invent page numbers that run across the whole omnibus, and it does not insert a generated title page between books.
Each book's cover image is copied with that book. The merger does not paint a new omnibus cover. A reader may show the first image marked as a cover, or none, depending on the device. If the shelf image matters, run Change EPUB Cover on the merged file.
Compared with Calibre's EpubMerge
Calibre does not ship a merge button. The usual desktop path is the EpubMerge plugin. It can add a title page per source book and write series metadata. It also sits inside Calibre, so a careless follow-up conversion can rewrite CSS you wanted left alone.
This page only relocates each book's files into a book-N folder, writes a new OPF, nav, and NCX, and leaves chapter markup alone. It does not write series indexes and it does not add title pages. Use EpubMerge when you want those generated pages. Use this when the job is the package and the reading order.
How to merge EPUB files
Add your EPUB files
Select two or more .epub files. They are read by your browser directly — nothing is uploaded anywhere.
Arrange the order and set a title
Move books up or down to set the reading order, and give the merged book a title for its metadata and table of contents.
Download the merged EPUB
The combined book — with a unified table of contents spanning every input — is saved straight back to your device.
Frequently asked questions
Does each book stay a part in the table of contents?
Yes. The new nav lists each source title, with that book's chapters nested under it. The old nav and NCX are not reused, because they point at paths that no longer exist.
Will links inside a chapter still work?
Links to other files in the same source book keep working. That book is copied as a folder, and relative URLs are unchanged. Links that pointed outside the EPUB, and highlights stored by a reading app, are not part of the file.
What happens to the covers?
Each cover image is copied with its book. No new omnibus cover is drawn. Some readers display the first image marked cover-image. Run Change EPUB Cover afterward if you want one specific shelf image.
Why is the cap 80 MB per file?
The book being copied has to sit in memory, then the next one is loaded. 80 MB each is the guardrail so a phone tab is less likely to be killed during the merge. There is no separate limit on how many files you add, past that memory ceiling.
How is this different from converting both books in Calibre?
Calibre's EpubMerge plugin can insert title pages and series metadata, and a later Convert step can rewrite CSS. This merger does not convert markup. It copies each book under a book-N folder and writes a new OPF, nav, and NCX around them.