KDP Paperback Cover Size, Spine Width and Bleed

KDP wants the whole cover as a single PDF: back cover, spine and front cover as one image. Its size is set by three things: the trim size, the spine width and the bleed. Bleed is 0.125 in (3.2 mm) added to the top, bottom and outside edges. The spine sides of the two panels get no bleed, because the panels meet there.

• Cover width = bleed + back cover width + spine width + front cover width + bleed.
• Cover height = bleed + trim height + bleed.
• In plain numbers: width = 2 × trim width + spine width + 0.25 in, and height = trim height + 0.25 in.

Worked example: a 6×9 in paperback with 300 pages on white paper has a spine of 300 × 0.002252 = 0.6756 in. The cover file is 6 + 0.6756 + 6 + 0.25 = 12.9256 in wide and 9 + 0.25 = 9.25 in tall, about 3,878 × 2,775 px at 300 DPI.

Spine width is the page count multiplied by a thickness factor that depends on the ink and paper you pick in KDP's print options. Use the final page count of the manuscript you upload, because the spine decides where the fold lines fall.

KDP also offers groundwood paper for black-ink paperbacks. Its factor is different, so take it from KDP's cover calculator and template generator instead of this table. Another KDP page, the Paperback Submission Guidelines, lists a single factor of 0.002347 for color paper, so when the exact number matters, let the calculator generate the template for your trim size, paper and page count.

Changing the paper after publishing changes the spine. KDP lets black-ink paperbacks switch between cream, white and groundwood paper and says you may need to upload a new cover file, depending on the page count. The ink type (black, standard color or premium color) is locked once the book is published.

6×9 in is the most common trim size for books in the US, and it is the default in KDP's print options. Custom paperback trim sizes can be 4 to 8.5 in wide and 6 to 11.69 in tall. The table applies the formula to a few combinations.

The same 300-page 6×9 in book is about 0.07 in wider on cream paper than on white. That shifts the front cover and the right-hand fold line by the same amount, so a file built for one paper type does not line up on the other.

Both bleeds are equal, so the spine sits in the exact middle of the file from left to right, and KDP asks for one continuous image centered on the spine. In the 6×9 in, 300-page example, the back cover and its left bleed take the first 6.125 in. The spine runs from 6.125 in to 6.8006 in. The front cover and its right bleed fill the rest, up to 12.9256 in.

Printing varies a little from book to book. KDP treats a spine shift of up to 3.2 mm in either direction as normal and advises against hard edges on the spine, because a shift makes them easy to see. A spine color that continues onto the back and front covers makes a small shift hard to notice.

As a rough check on spine text, a 7 pt line is about 0.1 in tall. With 0.0625 in of clearance on each side, the spine needs to be about 0.22 in wide, which is around 99 pages on white paper and 89 on cream. On the 300-page example, the usable text width is 0.6756 − 0.125 = 0.5506 in, about 14 mm.

1. Export one PDF that holds the back cover, spine and front cover as a single image. KDP will not convert cover files over 650 MB and recommends 40 MB or less.
2. Place images at 100% size, flattened to one layer, at 300 DPI or higher. KDP recommends CMYK images and advises against mixing color spaces in one file.
3. Leave out spot colors and embedded color profiles. KDP removes profiles before publishing, and spot colors do not work with its print-on-demand process. Convert them to CMYK.
4. Flatten transparencies and embed all fonts.
5. Remove crop marks, color bars, template text and any PDF creation guides.
6. Remove file security. Locked or encrypted files fail review.
7. Make sure the title, author name and edition on the cover match the book details you entered in KDP.

Order a proof copy before you launch. KDP's own help page points to a proof as the way to see the printed book before customers can buy it.

PiCraft's Book Cover Maker exports a paperback front image of 6.125×9.25 in at 300 DPI. That is the front panel of a 6×9 in wrap: 6 in of trim plus 0.125 in of bleed on the outer edge, and 0.125 in of bleed on the top and bottom. Place it against the top-right corner of your wrap file, with its left edge on the right-hand fold line of the spine.

The maker does not draw the back cover, the spine or the barcode area. Build those in the template from KDP's cover calculator and template generator, and carry the cover's colors across them so the wrap reads as one image. KDP recommends CMYK images for print covers and the PiCraft front file is a JPG, so check the colors on a proof copy.

The Kindle eBook cover is a separate file with its own rules, covered in the book cover size guide. If bleed and trim are new terms, what is bleed in printing explains them.