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KDP Cover Size Calculator

Work out the exact full-wrap cover size for a KDP paperback or hardcover, with spine width, bleed and a to-scale diagram you can check at a glance.

Your Inputs

Binding

Total pages in your final interior PDF.

in

KDP paperback covers use 0.125" (3.2 mm) on every outside edge.

Show dimensions in

Your Results

Total cover width
12.926"
328.31 mm
Total cover height
9.250"
234.95 mm
Full cover at 300 DPI
3,878 × 2,775 px
Minimum pixel size for a sharp print
Spine width
0.676"
300 pages, black ink, white paper
Front cover width
6.000"
Height 9.000"
Back cover width
6.000"
Height 9.000"
Bleed (each outside edge)
0.125"
Trimmed off after printing
Spine text
Pass: Allowed
Keep text 0.063" from each fold
Cover diagram, drawn to scale. Total 12.926" × 9.250". Back cover 6.000" wide, spine 0.676", front cover 6.000", bleed 0.125" on every outside edge.SpineBack Cover6.000" × 9.000"Front Cover6.000" × 9.000"6.000"6.000"Spine 0.676"Total width 12.926"Height 9.250"
Bleed (0.125", trimmed off)Trim line (finished cover)SpineSpine text safe area

Width = 0.125 + 6 + 0.6756 + 6 + 0.125; Height = 0.125 + 9 + 0.125

Before you export

Keep titles and important text at least 0.125" inside the trim line, export at 300 DPI or higher as a single PDF, and compare with KDP's downloadable cover template for your exact page count.

About the KDP Cover Size Calculator

A KDP print cover is one continuous image: back cover, spine and front cover side by side, plus extra artwork around the outside. For paperbacks that extra is bleed, 0.125" on every outside edge, which is trimmed away after printing. For hardcovers it is a much wider wrap that folds around the cover boards. Get any of these numbers wrong and KDP rejects the file or trims into your title.

This calculator takes your trim size, page count and paper type and returns every dimension your designer or design app needs: total width and height, the width of each panel, the spine, the bleed or wrap, and the full canvas in pixels at 300 DPI. The diagram is drawn to scale from the same numbers, so a thin 60-page spine looks thin and a 600-page spine looks chunky.

Switch the display between inches, millimetres and pixels to match how your software is set up, then copy, print or download a plain-text summary to send to a cover designer. Use it before you start designing, and again whenever your page count changes, because the spine changes with every page.

How It Works

The spine comes from page count multiplied by the thickness of one page for your paper: 0.002252" for white paper, 0.0025" for cream and 0.002347" for premium color. Paperback covers then add the front and back trim width plus 0.125" bleed on the left and right; the height is the trim height plus 0.125" top and bottom.

Hardcovers use a wider wrap of 0.591" and boards that are slightly larger than the trim (0.197" wider and 0.236" taller). The spine includes an extra 0.189" for the board and binding. These hardcover values are commonly published template measurements, kept in one configuration file as assumptions.

Spine text is allowed only from 79 pages. The diagram marks the spine text safe area, 0.0625" in from each fold, when your book qualifies.

Formula

Spine width
Spine = Page count × Paper thickness per page
Paperback width
Width = Bleed + Back trim width + Spine + Front trim width + Bleed
Paperback height
Height = Bleed + Trim height + Bleed
Hardcover width
Width = Wrap + Board + Spine + Board + Wrap
Pixels
Pixels = Inches × 300 (rounded)

Example

A 300-page 6" × 9" paperback on white paper

  1. Spine: 300 × 0.002252" = 0.6756".
  2. Width: 0.125" + 6" + 0.6756" + 6" + 0.125" = 12.9256".
  3. Height: 0.125" + 9" + 0.125" = 9.25".
  4. In millimetres: 328.31 × 234.95 mm. At 300 DPI: 3,878 × 2,775 pixels.

Set up a 12.9256" × 9.25" canvas (3,878 × 2,775 px), place a 0.6756" spine in the centre, and spine text is allowed.

Important Notes

  • Paperback values follow KDP's published cover rules. Always compare your final PDF with the cover template KDP generates for your exact book.
  • Hardcover wrap (0.591"), hinge (0.394") and board allowances are configurable assumptions, not official KDP figures. Download KDP's hardcover template before final export.
  • Your printed spine can shift by up to 0.0625" either way, so avoid borders or hard colour changes exactly on the fold.
  • Page count must be the final count of your interior PDF, including blank and front-matter pages.
  • Custom paperback trim sizes are supported between 4" and 8.5" wide and 6" and 11.69" tall.

Frequently Asked Questions

Why is my cover wider than two covers side by side?

Because the spine sits between them and the bleed adds 0.125" on the far left and far right. A 6" × 9" book is never 12" wide; with a 300-page white-paper spine it is 12.9256".

What pixel size should my cover be?

Multiply each inch dimension by 300. The calculator does this for you and shows the full canvas in pixels. Designing at a smaller size and enlarging later makes the print soft.

Does the cover size change if I add pages?

Yes. Every page adds its paper thickness to the spine, and the spine changes the total width. Recalculate whenever your interior page count changes, even by a few pages.

Can I put text on the spine?

Only if your book has at least 79 pages. Keep spine text at least 0.0625" from each fold so it does not wrap onto the front or back cover.

Is the hardcover size exact?

It uses commonly published hardcover template math, which matches KDP closely for most books. KDP generates an exact template for each hardcover, so treat this result as a planning size and confirm with the template.

Should I use cream or white paper for the calculation?

Use the paper you will select in KDP. Cream is thicker (0.0025" per page versus 0.002252" for white), so the same book has a wider spine on cream.

Does the bleed apply to the spine?

No. Bleed is only on the outside edges of the full cover: left, right, top and bottom. The spine sits between the back and front covers with no bleed of its own.

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