KDP Paperback Cover Guide 2026: Spine, Bleed, Barcode and Template

A printed paperback cover is not just a front-cover image. For Amazon KDP (and any print-on-demand printer), it is one large image that holds the back cover, the spine, and the front cover, all in a single piece, with precise bleed and a reserved area for the barcode. This guide explains how to build it correctly, step by step, with the official KDP values.

Quick answer: what is a full KDP cover?

A full cover (or "wrap") is a single PDF that reproduces the unfolded cover of a paperback: from left to right, the back cover, the spine, and the front cover. Its width depends on the page count of your interior (the more pages, the wider the spine). On KDP, you upload two separate files: the interior (the text, with no cover) and this full cover.

The full cover, panel by panel

When you physically unfold a paperback cover, you get three areas side by side:

• The front cover (on the right of the flat file): title, author, artwork. This is the face shown on the shelf.
• The spine (in the center): the edge of the book. It usually shows the title and the author's name, readable when the book stands upright.
• The back cover (on the left of the flat file): the blurb, sometimes a short bio, and the barcode area at the bottom.

The whole thing is printed on a single sheet, then folded around the interior block. That is why everything must fit in a single file, at the right dimensions.

The two files KDP needs

This is the point that confuses authors the most: print-on-demand requires two separate files.

1. The interior: the title page, the copyright page, and the chapters. It is a PDF without a cover or back cover.
2. The full cover: the back cover, spine, and front cover together, with bleed.

The page count of the interior (and only the interior) determines the spine width. The front and back covers are not part of it: they are the cover. To get the exact number, export your interior first and read its page count: that is the value to use when calculating the spine.

Calculating the spine width

The spine width is simple to compute:

Spine width = interior page count × thickness of one page

Page thickness depends on the paper and ink. Here are the official KDP values:

Example: a 250-page novel printed on cream paper will have a spine of 250 × 0.0635 = 15.9 mm, about 1.6 cm.

Choose the same paper you select for the interior on your platform: cream, slightly thicker, makes the spine a bit wider than white.

Spine text: from how many pages?

KDP only allows text on the spine from around 80 pages (below that, the spine is too thin for legible text). For a short book, leave the spine blank.

Bleed

Bleed is the extra margin that gets trimmed off at printing, to avoid a white sliver if the cut is slightly off. KDP requires 0.125 inch, that is 3.175 mm, on all four outer edges of the cover.

In practice, your cover image must extend 3.175 mm beyond the finished size, while keeping important text at least 0.25 inch (6.35 mm) away from the trim edges (the "safe zone").

The barcode area to keep clear

KDP prints a barcode on the back cover. You must leave room for it: a rectangle of about 2 × 1.2 inches (5.08 × 3.05 cm), placed at the bottom-right of the back cover, 0.25 inch (6.35 mm) from the spine and from the bottom edge.

Do not put important text (or a busy background) in that area: the barcode would cover it. The blurb, the author's name, and the ISBN must stay outside of it.

Note: if you publish on KDP with a free Amazon-assigned ISBN, KDP adds the barcode there automatically. So you do not have to draw it, just keep the area clear. (For everything about this, see our how to get an ISBN guide.)

Choosing the right trim size

KDP only accepts specific trim sizes. The most common ones for fiction:

Watch out: classic European sizes (such as the French 14 × 21 cm "roman") do not match a KDP trim exactly. If you target KDP, pick one of their sizes. If you go through a European printer or IngramSpark, European sizes are usually accepted. To choose well, read our print book format and dimensions guide.

The total size of the full cover is calculated as:

Total width = (2 × bleed) + (2 × trim width) + spine width

Total height = trim height + (2 × bleed)

Example at 6 × 9 inches, 200 pages, white paper: spine = 200 × 0.0572 = 11.44 mm; total width = 32.26 cm; total height = 23.50 cm.

Verify with the official KDP template (free)

KDP provides a free cover template calculator: you enter the trim size, page count, and paper, and it generates a PNG/PDF with the exact dimensions, spine, bleed, and barcode area. It is the reference tool to check that your cover is compliant.

Best practice before publishing:

1. Download the KDP template for your trim size and page count.
2. Overlay your cover on the template (or compare the measurements): total dimensions, spine, bleed, barcode position.
3. Once the book is created on KDP (without publishing it), use the online Previewer: it flags any issue. Creating a KDP account and using these tools is free.

Do it automatically with Folio Studio

Calculating the spine, handling bleed, reserving the barcode area, and lining up back cover, spine, and front cover by hand is tedious and error-prone. Folio Studio generates your full cover automatically: from the Print page (Pro plan), you pick the trim size and paper, enter the interior page count (Folio can calculate it for you), and the tool produces the PDF ready to upload to KDP, bleed and barcode area included. It also exports the interior alone, the second file you need. Discover Folio Studio.

In summary

• A full KDP cover = a single file with back cover + spine + front cover, plus bleed.
• You upload two files to KDP: the interior (no cover) and the full cover.
• Spine width = interior page count × paper thickness (white 0.0572; cream 0.0635; color 0.05961 mm). Spine text from around 80 pages.
• Bleed 3.175 mm on the edges; text 6.35 mm away from the cuts.
• Keep the barcode area clear (5.08 × 3.05 cm, bottom-right of the back cover, 6.35 mm from the spine and the edge).
• Use an exact KDP trim (6 × 9 inches, etc.) and verify with the free official template, or let Folio Studio generate everything.