Publishing your book

MechaSquid's Publish page turns a finished book into files the stores and printers accept: an EPUB for ebook stores, and a print-ready interior and cover (PDFs) for a paperback. It does not upload anything or sell anything for you; you upload the files to the services you choose. This guide explains the choices along the way. Sizes and rules were checked against the services on 2 October 2026; they change now and then, so check the service's own help before you upload.

You reach it from the book's Overview ("Publish this book") or from the book page (the first row of the Manuscript). Nothing on it changes your text.

Ebook or paperback, or both

An ebook is one EPUB file. E-readers let the reader choose the type and its size, so the look you pick is only the chapter openings and scene breaks. Ebook stores take it as it is.

A paperback is two PDFs: the inside pages (the interior) and the cover, which wraps around the back, the spine and the front in one piece. Every page is fixed: the size, the type and the margins are decided by you and set by MechaSquid.

Both use the same book details (title, blurb, keywords) and the same front and back matter (title page, copyright page, dedication, About the author, and so on), so you fill them in once.

Choosing a size

The trim size is the size of the finished book after the printer cuts the pages. You choose it once, at the print service, and the same file then sells in every country: Amazon prints a copy for a German reader in Europe from the same file as for an American reader. So the size is not about the marketplace; it is about what your readers expect a book like yours to look like, and which service prints it.

A service may offer more sizes than listed here. If you sell mostly through Amazon and your readers are in Europe, B-format is the usual choice; MechaSquid suggests it there, and Digest in the US and Canada. A larger size means fewer, fuller pages; a smaller one more pages and a thicker spine.

Paper and pages

Paper. Cream is softer on the eyes and usual for fiction. White suits pictures and non-fiction. Cream is a little thicker, so the same book has a slightly wider spine.

Type size. 11 pt is the usual size for a novel. A size larger makes the book easier to read and longer; the page count, and the printing price, follow.

Pages and the gutter. The gutter is the inside margin, by the binding. The thicker the book, the more of the page disappears into the fold, so print services ask for a wider gutter as the page count grows. MechaSquid sets it for you: it typesets the book, counts the pages, and sets it again if the count moved into another step.

The cover

A paperback cover is one picture that wraps around the book: the back on the left, the spine in the middle, the front on the right. The Cover tab of the viewer shows yours with guides drawn over it (they are never printed):

• Bleed (the outer band, 3 mm or ⅛ in): a picture that should reach the edge is printed past it, because the cutter is never exact. That band is cut off, so nothing important may sit in it.
• Trim line: where the book will be cut, its real edge.
• Spine: the back of the book, between the two folds. Its width is the page count times the paper's thickness, so MechaSquid works it out after typesetting. Below 100 pages a spine is too narrow for text and is left plain.
• Safe area: keep text and faces at least 6 mm (¼ in) inside the edges and away from the folds, so nothing is cut or lost in the binding. MechaSquid's layout already does.
• Barcode: print services put the ISBN barcode in a white box at the bottom right of the back. MechaSquid leaves that place empty.

The front is the book's main picture (set it on the book page). For a sharp print it needs about 300 pixels per inch: for a B-format book about 1560 × 2420 pixels, for Digest about 1690 × 2630. A picture made inside MechaSquid is smaller than that today; Make it warns you when yours will print soft. The title and your name are laid over the picture on dark bands, and the blurb goes on the back. Designing your own lettering comes later with the cover studio; until then you can also upload a finished front made elsewhere.

ISBNs

An ISBN is the book's international number; each format (ebook, paperback, hardback) needs its own.

• Amazon KDP and Lulu can give your paperback a free ISBN; the service is then named as the publisher, and that number can only be used with them.
• Your own ISBN comes from your country's ISBN agency (the International ISBN Agency's website lists them). With your own number you are the publisher, and you can sell the same edition through several services.
• An ebook usually needs none: the stores give it their own number.

Put the number in the book's details; it goes on the copyright page and into the ebook's details.

Where to print

• Amazon KDP prints your paperback when someone orders it on Amazon, in many countries, and sells your ebook on Kindle. Free to use; Amazon takes its share per copy.
• IngramSpark sends your paperback to bookshops and libraries through its wholesale network, and offers more sizes, including A5.
• Lulu prints copies to order and lets you sell from its own shop or your website, and ships author copies.

For each, start a new paperback, choose the same size and paper you chose in MechaSquid and a black-and-white interior, then upload the interior PDF as the manuscript and the cover PDF as a print-ready cover. The service checks both and shows a preview of the book. Many authors use Amazon for Amazon and IngramSpark for everyone else.

Before you publish

• Order a proof copy. A printed copy before you publish is the only way to see the colours, the spine and the margins as a reader will. Read it on paper; you will find things the screen hid.
• Check the spine text is centred and readable, and that nothing important is in the bleed.
• Answer the AI question honestly. Amazon asks whether the text, pictures or translation were made with AI. MechaSquid keeps a record of what you typed and what came from agents, which helps you answer.
• Mark it as published in MechaSquid when the book is out. That keeps the files as an edition and locks the book's chapters and scenes, so the published text cannot change by accident. A new edition unlocks it.

Ebook stores

Make the EPUB on the Ebook page, then open the store checklist: every field each store asks for, in its order, ready to copy, with a tick when done. Amazon KDP, Kobo Writing Life, Apple Books and Google Play each take the EPUB directly; Draft2Digital sends one upload to many stores. Categories are chosen in each store's own list when you upload.