Merge EPUB Files

Merge EPUB Files is built for readers and small publishers who hold a book split across several .epub files and want a single volume. The clearest fits are stitching a series into one omnibus, joining individual chapter EPUBs that were exported separately back into a complete book, and combining two or three volumes of the same work so they sit as one item in a library instead of several.

It is also useful for sharing and shelf-keeping: one file is easier to send, sideload to an e-reader, or archive than a folder of fragments. Because each source book becomes its own section with a generated title-page divider, anthologies of short works or collected drafts stay visibly separated inside the combined file rather than blurring together.

This is a reader-and-author convenience tool, not a typesetting or layout engine. If your goal is page-perfect design, a consistent house style across all chapters, or a press-ready master, treat the merged file as a starting point and finish it in dedicated EPUB editing software.

The flow is local and sequential. Drop your first .epub onto the upload area, then drop additional files one at a time; each appears in a numbered list showing its detected title, author, and size, with a trash icon to remove any entry. Order follows the order you add files, so to reorder you remove a book and re-add it in the position you want. Once at least two books are loaded, a details panel lets you set a final Title (default "Merged Book") and an optional Author before you press Merge.

Behind the scenes the tool writes a fresh EPUB 3 package in your browser: it copies every manifest file from each source under prefixed names, rebuilds the spine in reading order, inserts a centered title-page divider before each book after the first, and generates a new content.opf and nav table of contents. The download is named from your title plus "-merged.epub". Everything runs client-side, nothing is uploaded, and the files clear when the tab closes.

Supported input is reflowable EPUB only. It does not convert other formats, does not re-flow or restyle text, does not de-duplicate covers into one new cover, and does not edit chapter content. The generated contents list holds one top-level entry per book; it is a section map, not a deep chapter-by-chapter index.

Several limits are firm. Fixed-layout EPUBs (image-heavy comics, picture books, many cookbooks) are not supported for merging, DRM-protected files are detected and refused per file, and a single merge accepts at most ten EPUBs. A file that fails to open will report that it is not a valid EPUB rather than partially merging.

The most common surprise is styling. Each source book keeps its own CSS, and those stylesheets can conflict once combined, so fonts, margins, or headings may shift between sections. The combined table of contents is also coarse by design: it lists each book once and the links are placeholders, so it will not jump readers to individual chapters the way a natively authored TOC does.

Other mistakes to avoid: forgetting that only two or more books enable the Merge button, expecting drag-and-drop reordering (order is set by add order, adjusted by removing entries), and assuming the first book's cover becomes the merged cover (no new cover image is assigned). Mixed-language books are all tagged as English in the new package metadata.

Open the result in a real reader, not just a thumbnail. Confirm the books appear in the intended order, that each divider title page introduces the right section, and that the contents list shows every book you added. Page through the boundaries between books to catch CSS clashes, broken spacing, or a section that starts mid-stream, and verify the final title and author you set show up in the e-reader's book details.

Spot-check a few chapters inside each section for missing images, scrambled formatting, or dropped pages, since manifest files are copied rather than re-rendered. If you intend to sideload to a specific device or store, also run the file through a validator or that platform's own check, because a merged package can satisfy a reader yet still trip stricter ingestion rules.

For any official, financial, legal, or for-sale use, verify the merged output manually before distributing it. Treat the automatically generated metadata, contents, and section dividers as a draft to review, and confirm content integrity yourself rather than assuming the merge preserved everything exactly.