KDP cover size calculator

What a full-wrap cover is

A KDP paperback cover is one flat image that wraps around the book: the back cover on the left, the spine in the middle and the front cover on the right. Around all of it runs a strip of bleed that the printer trims off. You upload it as a single PDF, so its size has to match your book exactly: the trim size sets the two covers, and the page count and paper set the spine between them.

The cover size formula

Width = bleed + back cover + spine + front cover + bleed. Height = bleed + trim height + bleed. The bleed is 0.125 in on every outside edge, and the back and front covers are each the trim width. The spine is the page count times the paper factor (0.002252 in per page for white paper, 0.0025 in for cream).

6 × 9 in, 120 pages, white paper. The spine is 120 × 0.002252 = 0.27024 in. The width is 0.125 + 6 + 0.27024 in + 6 + 0.125 = 12.52024 in, and the height is 0.125 + 9 + 0.125 = 9.25 in. In pixels at 300 DPI that is 3757 × 2775.

8.5 × 11 in, 100 pages, cream paper. The spine is 100 × 0.0025 = 0.25 in, so the full cover is 17.5 × 11.25 in, or 5250 × 3375 px. Here it is to scale:

Bleed, trim and safe zones

The trim line is where the printed book ends. Anything between it and the outer edge of the file is bleed: extend your background colour or artwork into it, so no white edge shows if the cut is slightly off, but put nothing there you need to keep.

Inside the trim, keep text and logos at least 0.125 in away from the trim lines and the two fold lines. The folds are not exact: KDP allows 0.0625 in of movement on either side of each one, so a title placed right next to the spine can end up wrapping round it. The dashed boxes in the calculator’s diagram show these safe zones.

Spine text and its clearance

KDP prints spine text from 79 pages; its Cover Creator needs 80. On a thinner book, leave the spine plain, or it may slip onto the covers. When you do have spine text, keep 0.0625 in clear on each side of it: on the 6 × 9 in example that leaves 0.1452 in for the title and author name, set at 7 pt or larger.

The barcode box

If you don’t supply your own barcode, KDP prints one in a 2 × 1.2 in white box in the lower right corner of the back cover, on top of whatever is there. Keep that corner free of text and important artwork. KDP’s help pages give the size of the box but not its exact distance from the edges, so the diagram places it inside the safe zone as a guide; the template KDP generates for your book shows the exact spot.

Setting up a custom size in Canva

Canva and other design apps that work in pixels need the cover size at 300 DPI, KDP’s minimum for cover images.

1. Enter your trim size, page count and paper in the calculator and note the full cover size in pixels. It is rounded up, since a canvas can only be whole pixels and a smaller one would fall short of the cover. For the 6 × 9 in example it is 3757 × 2775 px.
2. Create a design with a custom size, choose pixels as the unit, and enter that width and height.
3. Mark the zones before you design. On the example, the trim line is 37.5 px in from every edge, and the spine runs from 1837.5 px to 1918.57 px across.
4. Export a PDF of the whole wrap, then check it against KDP’s file rules: one PDF with all three panels, fonts embedded, transparencies flattened and images in CMYK.

Common mistakes

• The wrong paper. Cream paper is thicker than white, so the same book on cream has a wider spine and a wider cover. Size the cover for the paper you will choose when you publish.
• Changing the page count after the cover is made. Adding puzzles, solutions or a blank page widens the spine and moves the front cover. Finish the interior, count its pages, then size the cover.
• Text in the bleed or on the folds. Anything past the trim line is cut off, and anything too close to a fold can wrap onto the spine. Keep text inside the safe zones.
• Artwork under the barcode box. KDP’s box covers it, so keep that corner plain.
• Uploading only the front cover. A paperback needs the whole wrap in one file.

Checking against KDP’s cover template

KDP has its own cover calculator and template generator. It asks for the same details as this calculator and makes a template for your exact book. To check one against the other:

1. Enter the same trim size, final page count and paper in both.
2. Compare the full cover width and height, and the spine width.
3. If they differ, one of the inputs has changed, usually the page count or the paper.
4. Design on KDP’s template, keeping text inside the safe zones and clear of the barcode box.
5. Order a printed proof before you publish and check the spine against the folds.

Cover size chart

Full cover sizes for common puzzle book trims, from the same KDP rules as the calculator:

Next steps

The spine width calculator covers the spine on its own, with the spine text rule. The KDP trim sizes guide lists every trim with its page limits and margins, and the book builder makes a whole puzzle interior as one print-ready PDF.

Checked against KDP’s help pages on October 26, 2026: Create a paperback cover, Paperback submission guidelines and Low-content books (the barcode box).