KDP Spine Width Calculator & Cover Template Generator

Enter your trim size, page count and paper stock. You'll get your exact spine width, the full wrap cover dimensions in inches and pixels, the interior gutter Amazon will require — and a blank template you can design over. Free, instant, no signup.

Spine width
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Full cover size
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includes 0.125" bleed all round
At 300 DPI
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canvas size for Canva / Photoshop
Interior gutter required
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inside margin at this page count
Outside margins minimum
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top, bottom & outer edge
Or use a ready-made cover template →

The blank template marks trim, bleed, spine folds, safe area and the barcode keep-out — open it in Canva at exactly the pixel size above and design on top. Prefer not to design at all? The Studio has four finished cover templates in five colourways, and it works the spine out from your book automatically. Free to use and export; a small credit on the back cover is removed with Pro.

How KDP spine width is calculated

Amazon provides an official cover calculator and templates. For a planning estimate, spine width is page count multiplied by the paper thickness factor:

Paper & inkInches per pageExample: 120 pages
Black ink, white paper0.0022520.2702"
Black ink, cream paper0.00250.3000"
Premium colour, white paper0.0023470.2816"

Note that cream paper is thicker than white. Switching paper stock after you've made your cover changes the spine — that alone is a common cause of rejected uploads.

Full wrap cover dimensions

Your cover is one single image or PDF covering back, spine and front together, with bleed on all four sides:

The 0.25" is 0.125" of bleed on each edge. Design anything that touches an edge right out into the bleed, and keep all text at least 0.25" inside the trim line.

Publishing a paperback? Get the KDP specs that actually matter

The margin, bleed, spine and paper rules KDP will reject you for, written out plainly — including the ones their own help pages bury. I’ll email the guide and let you know when the specs change.

Free, and you can leave any time. No spam, ever.

Three mistakes that get covers rejected

  1. The spine is calculated for the wrong paper. White and cream differ by about 10%. On a 300-page book that's nearly a tenth of an inch — plainly visible as a misaligned wrap.
  2. Spine text on a thin book. KDP only prints spine text on books with more than 79 pages. Below that, binding drift of up to 0.0625" would pull your text around onto the front cover. Leave thin spines blank, and in the same colour as the covers so any drift is invisible.
  3. Something sitting in the barcode area. Amazon prints a barcode in a 2" × 1.2" box at the bottom-right of your back cover. Put your blurb there and it will be covered up. The template below marks the exact zone.

Your interior has margin rules too

The gutter — the inside margin against the binding — grows with page count. Get it wrong and your text disappears into the spine:

Page countMinimum gutter
24 – 1500.375"
151 – 3000.500"
301 – 5000.625"
501 – 7000.750"
701 – 8280.875"

Outer, top and bottom margins must be at least 0.25" without bleed, or 0.375" with bleed. Books must be an even number of pages, and at least 24.

Build an interior before finalizing its cover

Try the 50 Word Searches starter: a 6 × 9 inch draft with 50 puzzles and answers. The example export is 62 pages. Edit the vocabulary and layout, export a free watermarked proof, then use its final page count to size your cover.

Start the 50-puzzle draft

Inspect the 62-page example PDF · See the complete walkthrough

This opens a separate starter; it does not transfer the calculator settings above. Re-export the interior and cover together after changing the book. A paid licence is required for clean book exports and commercial use.

More free tools: All free tools · KDP specs cheat sheet · Publishing guides · 88 printable word searches · Word search maker · Sudoku maker · Maze maker

Check your final files

This is a paperback planning tool for the trim and paper options shown. Odd manuscript counts are rounded up before calculating dimensions. Invalid counts are not silently reduced.

The PNG is a marked layout guide, not an upload-ready cover. It contains pixel dimensions for placement at 300 pixels per inch; set its physical size in your design tool and remove all guide labels from your finished artwork.

Confirm the final configuration with KDP’s cover calculator and its trim and page-count table. Sources checked 29 September 2026.

Still planning the interior? Inspect a complete 50-puzzle book proof before making your own.