Free tool
KDP paperback full cover size
Enter the trim size, pages and paper. The calculation shows the width and height of the open cover, with bleed, and the spine width.
Open cover, with bleed
- Width
- 12.700 in (322.6 mm)
- Height
- 9.250 in (235.0 mm)
- Spine
- 0.450 in (11.4 mm)
With 79 pages or more, text fits on the spine.
Formulas from KDP help, checked on October 17, 2026. For paperbacks; hardcover works differently, in the KDP calculator. Also calculate the printing cost and royalty.
Frequently asked questions
How is the full cover size calculated on KDP?+
Width = bleed + back cover width + spine + front cover width + bleed. Height = bleed + trim height + bleed. Bleed is 0.125 in (3.2 mm). The spine is the page count times the paper thickness.
How big is the cover of a 6 × 9 book with 200 pages?+
On white paper the spine is 0.450 in (200 × 0.002252) and the full cover comes to 12.700 × 9.250 in: 0.125 + 6 + 0.450 + 6 + 0.125 wide, and 0.125 + 9 + 0.125 tall.
How far from the edge can I put text on the cover?+
On the front and back, text stays at least 0.125 in (3.2 mm) inside the trim line. Spine text needs at least 0.0625 in (1.6 mm) of space on each side, and fits only from 79 pages.
Does changing the paper change the cover size?+
It changes the spine, and so the cover width. One sheet is 0.002252 in thick on white and standard color, 0.0025 on cream and 0.002347 on premium color. Hardcover works differently: use the KDP calculator.
CoAuthor builds the full cover already to KDP size
The account is free. The book costs from about US$ 7.70 (R$ 39, paid once, with no monthly fee). You are charged in Brazilian reais; the dollar figure uses the October 17, 2026 rate, about R$ 5.08 per US$ 1.