Text runs into the margins or the binding
Content must stay 0.25" from the trim edge on a page without bleed, 0.375" on one with it, and clear of the inside margin, which grows with page count.
Last reviewed
The three numbers that make up a margin
An interior page has a live area — the rectangle text and important images must stay inside — and the margins are what is left around it. On a page without bleed, the outside, top and bottom margins must be at least 0.25". On a page with bleed they must be at least 0.375", because the page is printed oversized and trimmed down, and the trim has a tolerance.
The inside margin, also called the gutter, is different. It is where the page disappears into the binding, so it has to grow as the book gets thicker: a fat book curves more at the spine and swallows more of the inner edge.
How the gutter grows with page count
The minimum gutter is set in bands of page count. A 200-page book needs 0.500"; a book at the 800-page maximum needs 0.875". That is why a manuscript laid out with a single fixed margin can pass at one length and fail after a revision adds a chapter.
As a worked example, a 6" x 9" book of 200 pages without bleed has a live area of 5.250" by 8.500": the trim width less the gutter and the outside margin, and the trim height less the top and bottom margins.
Mirrored margins
The gutter is on the right of a left-hand page and on the left of a right-hand page. A document with a fixed left margin therefore has its wide margin on the wrong side of every second page. Word calls the correct setting “Mirror margins”; InDesign and Affinity call them facing pages. Turn it on before you lay out a single page, because switching it later reflows the whole book.
Things that end up in the margin by accident
Body text is rarely the culprit. Look at these first:
- Page numbers and running heads placed too close to the edge.
- Tables and images wider than the text block.
- Text boxes and shapes positioned relative to the page rather than the margin.
- Pages imported from another document with different page setup.
Checking a finished file
The free margin calculator gives the minimums for your page count and trim. The pre-flight checker goes further: it reads where text actually sits on each page of your PDF and marks pages where content crosses into the margin, so you can see which pages to fix rather than hunting through the whole book.
What to do
- The outside, head and foot margins are 0.25" without bleed and 0.375" with it, measured from the trim edge rather than the page edge — a bleed page is larger than its trim on three sides.
- The inside (gutter) margin is not fixed: a 600 page book needs twice the inside margin of a 100 page one.
- Remember the gutter alternates sides. Left-hand and right-hand pages are mirrored, so a single fixed margin will fail on half the book.
- Run the PDF through pre-flight; pages with content outside the safe area are drawn with the offending text marked.
Work out your margins, free — no account needed, no upload, the answer in the page.Or check margins in the workspace to save it against a book.