KDP Margins and Gutter: Exact Settings for Every Trim Size

KDP rejected your file for "text outside margins"? It's almost always the gutter. The inside margin has to grow as your book gets thicker, and the outside margins change if you use bleed. Below are Amazon KDP's current minimums for every common page-count band, with and without bleed, plus suggested settings for 5 × 8, 5.5 × 8.5, 6 × 9 and 8.5 × 11 inch trim sizes, and how to set mirror margins in Word.

Key takeaways#

• The gutter (inside margin) is set by page count, not by trim size. Thicker books need a wider gutter so text doesn't vanish into the spine.
• Outside, top and bottom margins must be at least 0.25 in (6.4 mm) without bleed, or 0.375 in (9.6 mm) with bleed.
• Set mirror margins in Word (Layout → Margins → Mirrored) and put the gutter figure in the Inside field, not the separate Gutter field.
• Lock your interior page count before you design the cover. A font or margin change moves the spine width.
• Going to IngramSpark as well? Build to the stricter 0.5 in (13 mm) all-round margin once, so one PDF works on both platforms.

KDP margins in 30 seconds#

Every page has four margins: top, bottom, outside (the edge away from the spine) and inside (the gutter, next to the spine). Amazon KDP's paperback manuscript guide sets the inside margin from your final page count. Outside, top and bottom depend on whether the file uses bleed.

Bleed is the extra strip of artwork that runs past the trim line so colour or images print edge-to-edge with no white sliver. KDP asks for 0.125 in (3.2 mm) of bleed on the top, bottom and outside edges. The gutter edge never gets bleed.

These are minimums. For a cleaner look, most trade paperbacks use a bit more outside and top/bottom space than the floor, especially once you add headers and page numbers.

KDP gutter (inside margin) by page count#

KDP calculates your page count from the manuscript you upload, rounding up to an even number if needed. Match the gutter to that count, not to the count you hoped for.

Minimum vs recommended. The table above is the floor. If you sit right on 0.25 in outside with page numbers in the footer, any slight trim variance can clip them. A practical default for a text novel without bleed is 0.5 in (12.7 mm) outside and 0.75–1 in (19–25 mm) top and bottom once headers and page numbers are in. Leave a little breathing room so the text block doesn't feel jammed against the spine.

Outside margins with and without bleed#

Without bleed (most novels and text-only books):

• Outside, top and bottom: at least 0.25 in (6.4 mm)
• Live area: everything readable — body text, headers, footers, page numbers — must sit inside those margins

With bleed (workbooks, illustrated interiors, full-page backgrounds):

• Outside, top and bottom: at least 0.375 in (9.6 mm) from the trim edge
• Your PDF page size becomes trim width + 0.125 in, and trim height + 0.25 in (bleed on top and bottom)
• Artwork that should print to the edge must extend all the way to the bleed edge; text still stays inside the live area

"Live area" simply means the safe rectangle where nothing important gets cut. Background colour can leave it. Words and page numbers must not.

Recommended margins by trim size#

Trim size is the finished book size after trimming. Margins are independent of trim size for KDP's minimums — the gutter still follows page count — but the feel of the page changes with the trim. A 5 × 8 in novel with a 0.5 in gutter and 0.5 in outside leaves a narrower text block than the same margins on 6 × 9. If you're still choosing a size, start with how to choose a book trim size.

Suggested starting points below assume a typical novel-length interior around 250–300 pages (so a 0.5 in / 12.7 mm gutter), no bleed, and room for headers. Adjust the gutter up if your page count crosses into the next band.

5 × 8 in (12.7 × 20.32 cm)

Popular for genre fiction and shorter novels.

• Page size, no bleed: 5 × 8 in
• Page size with bleed: 5.125 × 8.25 in
• Suggested: Inside 0.5 in · Outside 0.5 in · Top 0.75 in · Bottom 0.75 in
• Keep body text around 11 pt with comfortable leading; this trim is narrower, so don't starve the outside margin to fit more words per line

5.5 × 8.5 in (13.97 × 21.59 cm)

A common US trade size that still feels portable.

• Page size, no bleed: 5.5 × 8.5 in
• Page size with bleed: 5.625 × 8.75 in
• Suggested: Inside 0.5 in · Outside 0.5 in · Top 0.75 in · Bottom 0.75 in
• Good middle ground when 6 × 9 feels large and 5 × 8 feels tight

6 × 9 in (15.24 × 22.86 cm)

The most common KDP paperback trim for novels and non-fiction.

• Page size, no bleed: 6 × 9 in
• Page size with bleed: 6.125 × 9.25 in
• Suggested for ~250–300 pages: Inside 0.5 in · Outside 0.5–0.6 in · Top 0.75–0.875 in · Bottom 0.75–0.875 in
• For a 320-page book you'd step the inside margin up to 0.625 in (15.9 mm)
• Plenty of room for chapter openers and a readable line length at 11–12 pt

8.5 × 11 in (21.59 × 27.94 cm)

Workbooks, journals, manuals and some textbooks. Often uses bleed for full-page exercises or shaded boxes.

• Page size, no bleed: 8.5 × 11 in
• Page size with bleed: 8.625 × 11.25 in
• Suggested without bleed: Inside per page count · Outside 0.5–0.75 in · Top/Bottom 0.75 in
• Suggested with bleed: Inside per page count · Outside, top and bottom at least 0.375 in from trim (and usually more for a workbook that readers write in)
• Wide pages invite two-column layouts; keep both columns inside the live area

How to set mirror margins in Word#

Word's default "Normal" margins are wrong for a paperback. You need mirrored (facing) pages so the larger inside margin flips correctly on left and right pages.

1. 1Set the page size first (Layout → Size → More Paper Sizes). Enter your trim width and height. If you use bleed, enter the larger bleed page size.
2. 2Layout → Margins → Custom Margins.
3. 3Under Pages → Multiple pages, choose Mirror margins.
4. 4Enter Top, Bottom, Inside and Outside using the chart above for your page count and bleed choice.
5. 5Leave the separate Gutter field at 0. Put the gutter figure in Inside. (KDP's own Word walkthrough says the same.)
6. 6Apply to Whole document, then OK.
7. 7Add section breaks where front matter needs different headers or page-number styles. Don't reset margins per section unless you mean to.
8. 8Export or save as PDF and check the PDF page size matches what you set. A Letter or A4 export is a common reason KDP flags the file.

A fuller Word walkthrough for KDP print and Kindle is coming; until then, pair this with our Kindle formatting guide and the older Amazon KDP formatting overview.

Why your page count changes your margins (and your spine)#

Change the body font from 12 pt to 11 pt and you can shed dozens of pages. Those pages can drop you into a smaller gutter band — or push you into a larger one if you widen the type. The cover spine is calculated from the final page count and paper type, so locking the interior first avoids reprinting the wrap.

Use the free cover size calculator once the page count is stable, and the print cost tool if you want to see how page count hits your royalty.

Top 5 margin errors KDP flags (and the fix)#

1. 1Page numbers or headers in the margin zone. Pull them inside the live area, or widen top/bottom. Sitting on the 0.25 in floor is asking for a trim nip.
2. 2Full-bleed images on a no-bleed file. Either extend the PDF to the bleed page size and turn bleed on in KDP, or keep images inside the margins.
3. 3Wrong PDF page size. The PDF must match trim (or trim + bleed). Exporting from Word at A4 or Letter when you set 6 × 9 in the document is a classic miss — check the PDF properties before upload.
4. 4Gutter set for the wrong page count. You formatted at 0.375 in for a short draft, then the finished book landed at 280 pages. Re-open margins and move Inside to 0.5 in.
5. 5Headers too close to the edge. Give headers and the first line of body text clear air from the trim. If Print Previewer shades a strip over your running head, widen the top margin.

If you'd rather not fight Word, our print files are delivered with and without bleed, prepared for KDP and IngramSpark. The free first-chapter sample on the book formatting page shows the difference on your own manuscript.

Publishing on IngramSpark too?#

IngramSpark's file creation guidance recommends a flat 0.5 in (13 mm) margin on all sides for the text block, plus a 0.125 in (3 mm) no-ink strip on the bind edge for perfect-bound books. Bleed, when used, is on the three outer edges only. That is stricter than KDP's 0.25 in no-bleed floor. If you want one interior PDF for both Amazon and bookshop distribution, build to IngramSpark's 0.5 in all round and you'll clear KDP as well. A dedicated IngramSpark formatting walkthrough is on the schedule next; for royalty differences see Amazon KDP vs IngramSpark royalties.

Frequently asked questions#

Next step#

Would rather not wrestle Word? We'll format your first chapter free, so you can see the difference before you pay anything. Full print and ebook formatting starts at £197 ($249), with files prepared for KDP and IngramSpark.