# Choosing trim sizes, gutter margins, and bleed for print PDFs

> BookZeta Print PDF specs explained: standard book trim sizes, KDP 3-edge bleed vs commercial 4-edge bleed, inside gutter margins, and spine width calculation.

- **Category:** [Exporting & Publishing](https://bookzeta.ai/help-center/exporting-publishing)
- **Canonical URL:** https://bookzeta.ai/help-center/exporting-publishing/kdp-trim-sizes-margins-and-bleed
- **Last Updated:** 2026-11-12

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When you export a **Print PDF** or **Print Cover PDF** from BookZeta, the print settings modal lets you match the exact physical specifications required by Amazon KDP, IngramSpark, or a local commercial printer. This reference supplements [Exporting a print-ready interior](/help-center/exporting-publishing/print-ready-interior) with the exact dimensions, margin formulas, and bleed rules BookZeta uses under the hood.

## Supported trim sizes

BookZeta formats interiors and wraparound covers across standard publishing sizes (width x height in inches):

| Preset | Trim Size | Typical Use |
| --- | --- | --- |
| **US Trade Standard** | `6" x 9"` | Full-length novels, trade nonfiction, graphic novels |
| **Digest Format** | `5.5" x 8.5"` | Literary fiction, memoirs, mid-length novels |
| **Novella / Compact** | `5" x 8"` | Novellas, short fiction, poetry |
| **Mass Market** | `4.25" x 6.87"` | Pocket-sized genre paperbacks |
| **Textbook** | `8.5" x 11"` | Workbooks, manuals, study guides |
| **Square** | `8" x 8"` | Children's picture books |
| **Children's Portrait** | `8" x 10"` | Classic vertical picture books |
| **Children's Landscape** | `10" x 8"` | Wide-format picture books |
| **US Comic** | `6.625" x 10.25"` | Standard American comic issues and trade paperbacks |
| **Standard / Signature Manga** | `5" x 7.5"` / `5.75" x 8.25"` | Manga volumes |
| **European Album / Magazine** | `8.4" x 11.6"` / `8" x 10.5"` | Bande dessinée albums and illustrated magazines |

For advice on picking between `6" x 9"`, `5.5" x 8.5"`, and `5" x 8"` for your word count, see [Standard Book Trim Sizes, Margins, and Bleed for Amazon KDP](/blog/book-trim-sizes-and-margins-kdp).

## KDP bleed vs Commercial bleed

When artwork extends to the edge of the page, BookZeta adds **`0.125"` (1/8 inch) of bleed** at 300 DPI and converts print PDFs to **CMYK** with zero crop or registration marks (which print-on-demand uploaders reject).

In the Print PDF export options, pick the **Target** that matches your printer:

- **KDP (`target: kdp`)** — On interior pages, KDP adds `0.125"` bleed to the **top, bottom, and outside edge only** (never the inside spine edge). A `6" x 9"` bleed interior exports at **`6.125" x 9.25"`**; an `8" x 8"` picture book exports at **`8.125" x 8.25"`**.
- **Commercial (`target: commercial`)** — Adds `0.125"` bleed on **all four edges** (`6.25" x 9.25"` for a `6" x 9"` trim), which commercial offset and saddle-stitch printers expect.
- **Full Print Covers** always include `0.125"` bleed around all four outer edges of the combined Back + Spine + Front spread.

## Novel margins and dynamic gutter scaling

For text-heavy Writer Mode books, BookZeta applies comfortable trade margins and automatically widens the inside binding gutter as your page count grows:

- **Top & bottom margins:** `0.75"`
- **Outside margin:** `0.625"`
- **Inside (gutter) margin:** starts at **`0.875"`** and adds **`0.0625"` per 100 pages** so thick novels open cleanly without swallowing text into the spine glue.

## Paper type, binding, and spine width

In the export modal you can also configure:

- **Paper (`White` vs `Cream`):** Calculates spine width automatically using KDP's standard pages-per-inch thickness—`0.002252"` per page for White paper and `0.002500"` per page for Cream paper (with an optional manual **Spine Override** if a specialty printer supplies a custom template).
- **Binding (`Perfect` vs `Saddle-Stitch`):** Perfect-bound paperbacks calculate a spine width from your page count; saddle-stitch booklets fold on staples with a `0"` spine.
- **Pad to multiple of 4:** For saddle-stitch comics and picture books, enabling **Pad to 4** injects clean blank endpapers before the back cover so your total page count is divisible by four.

Always lock your interior PDF *before* exporting your wraparound cover from the [Cover Editor](/help-center/visual-tools/cover-editor), and verify the finished files against [Amazon KDP rules](/help-center/self-publishing-rules/amazon-kdp-rules).