The most used Amazon KDP trim sizes, plus A5 for the European market.
| Size | Recommended use |
|---|---|
| 6 × 9 in | Non-fiction — the most used on KDP |
| 5.5 × 8.5 in | Fiction — the most popular for indie authors |
| 5 × 8 in | Compact fiction (romance, thriller) |
| 5.25 × 8 in | Fiction, roomier variant |
| 8.5 × 11 in | Workbooks, illustrated, coloring books |
| A5 | European standard |