Choosing a Trim Size: How Big Should Your Book Be?

For most self-published books the answer is one of a handful of standard trim sizes: 5x8, 5.25x8, and 5.5x8.5 suit novels and memoirs, 6x9 is the workhorse for general nonfiction (and the single most popular size overall), and 7x10 or 8.5x11 handle workbooks, manuals, and graphics-heavy titles. Pick a standard size that matches your genre, because it prints cheaply, sits comfortably on a shelf, and signals to readers that your book belongs next to the others in its category.

Trim size is the width by height of your finished book, measured after the pages are trimmed at the last stage of printing. It is one of the first decisions you make, because it drives your page count, your printing cost, and how your book reads and feels in the hand. The good news is that you do not have to invent a size. A short list of industry standards covers almost every book, and staying on that list keeps your options open and your costs down.

The common trim sizes

Print-on-demand printers offer a fixed menu of sizes, and the ones self-publishers reach for most are:

• 5 x 8 inches and 5.25 x 8 inches: compact and intimate, good for shorter novels, novellas, poetry, and gift-sized books.
• 5.5 x 8.5 inches: a classic trade paperback size, arguably the most popular choice for fiction and memoir.
• 6 x 9 inches: the most widely used size of all, the default for general nonfiction and longer novels, and the most common hardcover size.
• 7 x 10 inches: roomier pages for sidebars, pull quotes, and reference material.
• 8.5 x 11 inches: manuals, workbooks, and instructional books with lots of graphics, which suit a large page and even a two-column layout.

A5 (roughly 5.83 x 8.27 inches) and A4 (roughly 8.27 x 11.69 inches) round out the list for authors outside the US who want metric-standard sizes. Sticking to this menu matters, because a nonstandard size can cost more to print or may not be offered at all by your chosen printer.

Genre conventions

Readers form expectations from the books already on the shelf, so matching your genre's usual size makes your book look like it belongs. A few well-worn conventions:

• Fiction (novels, short stories): 5.5 x 8.5 is the popular default, with 5.25 x 8 for a more intimate feel on shorter books. Longer novels often move up to 6 x 9 to avoid becoming too thick.
• Memoir: the same sizes as fiction, most often 5.5 x 8.5.
• General nonfiction and business: 6 x 9, the most popular size of all. Step up to 7 x 10 when you need room for sidebars, charts, or pull quotes.
• Workbooks, manuals, and reference: 7 x 10 or 8.5 x 11, where the extra width supports diagrams, worksheets, or a two-column layout.
• Poetry: smaller sizes such as 5 x 8 or 5.25 x 8, which suit short lines and generous white space.

Why 6x9 dominates nonfiction and smaller sizes suit fiction

The pattern is not an accident. 6 x 9 gives nonfiction the page area it needs for headings, subheads, lists, tables, and the occasional figure, and it is the standard hardcover size, so a nonfiction title in 6 x 9 reads as serious and professional. It is also economical: a larger page holds more words, so the same manuscript runs fewer pages.

Fiction leans the other way. A novel is mostly running text, and a 5.25 x 8 or 5.5 x 8.5 page feels intimate and comfortable to hold for long stretches, closer to the trade paperbacks readers already associate with storytelling. The smaller page is part of the reading experience, not just a cost decision.

Page count and cost

Trim size and page count are linked, and both feed your printing cost. Here is how to think about it:

1. A larger page holds more words, so it lowers your page count. The same manuscript is shorter in 6 x 9 than in 5 x 8. Fewer pages usually means a lower per-copy print cost, which matters most for long books.
2. A smaller page raises the page count but gives you that compact, intimate feel. For a novel, the reading experience can be worth the extra pages.
3. Page count sets your spine width and your floor price. Print-on-demand cost is driven largely by page count, so the trim size you pick quietly decides how thick your book is and how low you can price it while staying profitable.
4. Paper color can restrict your size. Cream paper, which many authors prefer for novels because it is easier on the eyes, is available only in certain trim sizes at some printers, so confirm the combination you want before committing.

One more caution: be wary of going bigger than 7 x 10 unless your content truly needs it. Oversized books do not fit some bookstore and home shelves, and unless you are making an art or photo book, an odd large size can work against you.

How to decide

Start with your genre's convention, confirm the size is on your printer's standard list, and check your paper choice against it. If this is your first book and it is a novel or memoir, 5.5 x 8.5 is a safe, readable choice. If it is nonfiction, 6 x 9 is the reliable default. Our professionally designed book interior templates come in all the common trim sizes, so you can format to the exact dimensions your genre expects without doing the margin and spine math yourself. And if you would rather hand it off entirely, Cantos, our team's book-design AI, will typeset your book at the trim size you choose, with a free preview of your own pages first.

Frequently asked questions

What is the most popular book trim size?

6 x 9 inches is the single most popular size, especially for general nonfiction and hardcovers, because it holds more text per page and reads as professional. For fiction and memoir, 5.5 x 8.5 is the most common choice, with 5.25 x 8 close behind for shorter, more intimate books.

Does trim size affect printing cost?

Yes, indirectly. A larger trim size fits more words per page, which lowers your page count, and print-on-demand cost is driven largely by page count. So a bigger page can mean a cheaper book, especially for long titles, while a smaller page raises the count but gives fiction a more comfortable feel. Trim size also sets your spine width.

Can I choose any size I want?

In practice, no. Print-on-demand printers offer a fixed menu of standard sizes, and picking one keeps your book affordable and available. Nonstandard sizes may cost more or not be offered, and books larger than about 7 x 10 can be awkward to shelve. Unless you have a specific reason, choose an industry-standard size that matches your genre.