What to enter
- Page count. Use your final interior file's page count, blank pages included. Odd counts round up to the next even number, and that number sets the margins, spine, and page range check.
- Interior has bleed. Tick it only if something in your interior, like a photo or background color, runs off the page edge. The cover always has bleed either way.
- DPI. Changes only the pixel column. Use 300 for KDP.
- Reading direction. Right to left swaps the back and front panels. It doesn't check whether KDP prints your language that way.
How to read the result
- Cover file is the full size of your cover PDF. It's exact for a paperback and an estimate for a hardcover.
- Margins are the smallest KDP allows for this setup.
- Page range says whether the even page count fits KDP's range for this trim, ink, and paper. Outside it, you still get dimensions, but KDP won't print that setup.
- Copy setup receipt copies the key numbers as text, ready to send to a cover designer.
A 300-page 6 × 9 in paperback
Example
Black and white on white paper, no interior bleed. The spine is 300 × 0.002252 = 0.6756 in. The cover is 0.125 + 6 + 0.6756 + 6 + 0.125 = 12.9256 in wide and 9 + 0.25 = 9.25 in tall, or 3878 × 2775 pixels at 300 DPI. The inside margin is 0.5 in, and the other margins are 0.25 in.
How is KDP cover size calculated?
A paperback cover is the back, spine, and front side by side, plus 0.125 in of bleed on each outer edge. Bleed is extra image that gets trimmed off, so no white line shows at the edge.
Paperback cover size
Formula
Spine: page count × paper thickness
Width: 0.125 + trim width + spine + trim width + 0.125
Height: 0.125 + trim height + 0.125
| Ink and paper | Thickness per page |
|---|---|
| Black and white on white, or standard color | 0.002252 in |
| Black and white on cream | 0.0025 in |
| Premium color | 0.002347 in |
| Black and white on groundwood | 0.00235 in |
KDP's paperback cover guide lists the white, cream, and color multipliers. Its paperback submission guidelines list groundwood.
Use at least 80 effective pages for spine text. KDP's guide has conflicting wording about 79 pages, and Cover Creator requires 80.
What margins does KDP require?
The inside margin, next to the spine, grows with page count so text doesn't disappear into the binding.
| Pages | Inside margin |
|---|---|
| 24 to 150 | 0.375 in |
| 151 to 300 | 0.5 in |
| 301 to 500 | 0.625 in |
| 501 to 700 | 0.75 in |
| 701 to 828 | 0.875 in |
Outside, top, and bottom margins are 0.25 in, or 0.375 in with bleed. These are the least KDP allows in its paperback submission guidelines, not a design recommendation.
One page can move you into the next band. A 300-page book needs a 0.5 in inside margin, but 301 pages rounds up to 302 and needs 0.625 in.
What does interior bleed change?
Each page gets 0.125 in wider and 0.25 in taller, so a 6 × 9 in book needs 6.125 × 9.25 in pages. Width grows on the outside edge only, because the bound edge isn't trimmed. See KDP's bleed and trim guide.
Why is the hardcover size an estimate?
KDP documents the parts of a hardcover cover, a 0.51 in wrap around the board and a 0.4 in hinge beside the spine, but not one formula for the full size. It sends you to its cover calculator instead. See KDP's hardcover cover guide.
This calculator adds the wrap and hinge to both sides and uses paperback paper thickness for the spine. For a 300-page 6 × 9 in hardcover with black ink on white paper, that's about 14.4956 × 10.02 in. Get the final size from KDP's cover calculator before you design.
What doesn't this calculator check?
It uses KDP's US print specs, rechecked on October 4, 2026, and runs in your browser. It doesn't read your files or decide whether KDP will accept your book. Next steps:
- Check your exported PDF with the KDP PDF preflight checker.
- Check that your images are sharp enough with the KDP image DPI checker.
- Set your price with the KDP royalty calculator.