KDP trim sizes for paperback and hardcover books

Paperback trim sizes (kdp.amazon.com)

All sizes are width x height.

Regular trim: 5 x 8 in, 5.06 x 7.81 in, 5.25 x 8 in, 5.5 x 8.5 in, 6 x 9 in.

Large trim: 6.14 x 9.21 in, 6.69 x 9.61 in, 7 x 10 in, 7.44 x 9.69 in, 7.5 x 9.25 in, 8 x 10 in, 8.25 x 6 in (landscape), 8.25 x 8.25 in, 8.27 x 11.69 in (A4), 8.5 x 8.5 in, 8.5 x 11 in.

If none fits, paperbacks accept a custom size between 4 and 8.5 in wide and 6 and 11.69 in tall.

Paper and ink availability is broad: black ink on white, cream or groundwood paper and premium color work on every listed size, while standard color is not available on 8.27 x 11.69 in.

Hardcover trim sizes

Hardcovers are limited to five sizes: 5.5 x 8.5 in and 6 x 9 in (regular), and 6.14 x 9.21 in, 7 x 10 in and 8.25 x 11 in (large). Hardcovers support black ink on white or cream paper and premium color; standard color and groundwood are not offered. Hardcover is not available on kdp.amazon.co.jp, which has its own paperback size list (for example 4.06 x 7.17 in and 5.83 x 8.27 in).

Why “regular” or “large” matters

KDP uses the regular/large split, not the exact size, for printing cost. A book at 6.14 x 9.21 in pays the large-trim rate even though it is only slightly bigger than 6 x 9 in.

Common mistakes

• Formatting the interior before choosing the trim. Margins, page count and cover width all depend on it.
• Picking 8.5 x 11 in for a long book: black ink white paper tops out at 590 pages on that size versus 828 pages on 6 x 9 in.
• Assuming a hardcover can reuse any paperback size. Only the five hardcover sizes work.

Amazon changes these rules; the linked KDP help pages are the authority.