Trim size is the finished size
Trim describes the width and height of a page after cutting. It does not include the extra artwork used for bleed. A 6 × 9 inch book stays a 6 × 9 inch book even when its production file includes bleed.
Begin with books your readers already enjoy. Hold a few of them, measure the pages and notice how they feel. A pocket-sized devotional, a workbook and a picture book ask different things of the reader.
Match the shape to the content
A narrow page can suit continuous prose. A wider page offers more room for tables, photographs and writing exercises. Square pages can work well with illustrations, but check how your existing artwork fits before choosing them. Cropping a painting to a new shape may remove something that matters.
Our trim comparison tool shows proportions. It does not promise that every size is available for every binding, paper or printer. Check the platform’s current print options before making the design final.
Understand the effect on length
A larger text area usually holds more words, but page count also depends on type size, line spacing and chapter breaks. Do not shrink the type just to reach a cheaper page count. Readability belongs in the decision.
For planning, compare the same word count at two sizes in the page-count estimator. Treat the results as a budget range, not a final specification. Illustrations, poems and short chapters can change the result substantially.
Choose before the cover is finished
Changing trim size affects both the interior and the cover. It may also change the final page count and spine. Settle the interior first, then generate a cover template for the precise printer, binding and paper.
If you plan to use both KDP and IngramSpark, choose a format supported by both. Keep a short specification sheet for each edition so the correct file goes to the correct platform.
Official references
Check the current requirements for your chosen edition before final export.