KDP trim sizes explained: which size should your book be?
Trim size is the finished size of your printed book. It affects your page count, your printing cost and how your book feels in a reader's hands. Most authors are best off copying what the bestsellers in their genre use.
Step by step
- Look at your genre. Check the paperback details of a few bestsellers in your category on Amazon.
- Pick a size in KDP. Choose it on your KDP paperback setup page.
- Format at that size. Choose the same trim size in Postscript's Book Formatter.
- Export and upload. Download the print PDF and upload it to KDP.
The common sizes
6 × 9 in: the default for most novels, memoirs and non-fiction. 5.5 × 8.5 in: a popular, slightly smaller size for fiction and poetry. 5 × 8 in and 5.25 × 8 in: compact sizes for shorter novels. 6.14 × 9.21 in: the size of many hardbacks and trade non-fiction. 7 × 10 in and 8 × 10 in: workbooks, textbooks and illustrated books. 8.5 × 8.5 in: square picture books. 8.5 × 11 in: manuals and large workbooks.
Smaller size, more pages
The same manuscript runs to more pages at 5 × 8 than at 6 × 9, and KDP's printing cost rises with page count. If your book is long, a larger trim size can lower the price you need to charge.
Margins change with size too
Smaller trim sizes leave less room on each page, so keep margins sensible rather than squeezing them to fit more words. Very thick books also need a wider inside margin so the text doesn't disappear into the spine. The Book Formatter lets you adjust margins and shows the result in the preview.
Questions
What size are most novels?
6 × 9 inches is the most common on KDP, with 5.5 × 8.5 close behind.
Can I change the size later?
Yes, but you need a new interior and a new cover, since the spine width changes too.
Does the Book Formatter have A5?
Yes, along with A4 for printing outside the US.
Is the Book Formatter free?
For books up to 10,000 words and 10 chapters, yes. Full-length books need Pro ($24.99 once).
More guides
How to format a book for print and ebook (free for short books)
Format your manuscript into a print-ready PDF in KDP trim sizes plus an EPUB. Free for books up to 10,000 words; Pro for full-length novels.
How to format a paperback for Amazon KDP
Step by step: lay out a KDP-ready paperback interior in the right trim size, check it, and fix common KDP upload errors.
How to turn a Word manuscript into an EPUB ebook
Create an EPUB with chapters, a title page and a contents list from your Word or text manuscript, free in your browser.