Self Publishing for Writers blog

blog Home




Book Basics





I'm Charlie
Book Designer & Self Publishing coach

Book trim size


January 3, 2021

Ten things to consider when deciding your book’s size.

There are many different trim sizes for books, so how do you choose the right size? There are standard book sizes, but as a sell publisher, you also have some leeway. To decide the right size for your book, you want to consider your book’s genre, how it will be displayed, spine size, content, user experience, and who will be printing and fulfilling your book orders. Below are the things I consider when determining book size.

Some things to remember when talking about book sizes

The term trim size is a printer’s term referring to the final dimensions or cut-size of a book. Book dimensions list width first, then height. U.S. book sizes are referred to in inches, while in Europe, millimeters. It is essential to always be clear with whether the book is landscape or portrait. It matters. A landscape book may not fit as efficiently on a parent sheet of paper and can cost considerably more than the same size book in portrait orientation. 

1. Is the book trim size compatible with other books in your genre?

There are no hard and fast rules on what size book to choose, but you want your book to fit on shelves with books of the same genre. Your potential readers will gravitate to what is familiar when looking for a book in their preferred genre, so it is well worth researching and considering what dimensions are typical in your genre. A Fact-finding Mission is a great way to explore books within your genre.

2. Does it stand out on the shelf?

Will it stand out against other books in its genre?

3. Is the spine big enough to print the title?

(you may need to decide this in the next step—calculating page count) The trim size will determine how many pages you have. If you have a large manuscript, your book’s trim size can be larger. If you have a short book, a smaller trim size can give you a larger spine and give your book more substance. A larger spine will stand out more on a bookshelf. But remember, more pages usually mean the book will cost more, but the cost may be worth it by making the book more user friendly or making it stand out on a shelf.

4. Does the content fit comfortably onto the page or spread?

To determine your book trim size, you want to consider how your content will fit on a spread. The pages that face each other when you open the book is called a spread. Like illustrated workbooks or daily meditations, some books may require the content to fit on a page or a spread. I recommend that you spend some time in a bookstore and look at books in your genre and complete your Fact-finding Mission Workbook. Look at which books stand out to you. Look at layouts you like. You will notice that more design intensive books like cookbooks, manuals, and reference books are usually larger to fit related content on a spread. The same goes for illustrated children’s books. Text only chapter books are often smaller, more portable. Look at the margins of the books you like. Are the margins large, or does the text come close to the page edges? 

5. Is it easy to package and ship? Do you know the postage?

If you are fulfilling orders by mail, you may want to consider a book size that fits nicely into a common mailer envelope. The cost of postage may also be a consideration.

6. Is your book a novel with just text with chapter breaks?

With unillustrated chapter books, you have the most flexibility in size, but they rarely go larger than 6 x 9. 

7. Does your book require to be laid out with left and right-hand spreads?

You may have a book of yoga poses or other content that needs to fit on facing pages. If this is the case, then your book’s trim size may be determined by your content.  With books like this, I often take a few of the pages with the most content and a few with the least and experiment with page layout to see what size works best for my material.

8. Does your book have photographs? If so, how many and how big do you want them?

If you have detailed maps or photos that need to print large or want multiple photos on a page, then a larger trim size may be right for you.

9. Is your book something like a cookbook with full-page photos, smaller photos, and special text formatting?

Books like cookbooks often use larger trim sizes to accommodate photos and also to be able to lay open on their own.

10. Do you want to print both offset and POD?

You may want to consider a size available in both print-on-demand and offset. That way, your book can grow with you. Research all the options you may want to consider in the future. Let’s say right now you are not concerned with distributing through Amazon, but you may want to in the future. Then it may be useful to pick a size offered through Create Space as well as the printer you have chosen.

Choosing your book size is not a one size fits all situation.  But if you weigh these considerations to determine your book trim size, you can make the best choice for your book.

Delivered straight to your inbox every Sunday!
Sign up now! 

Self-publishing for

Subscribe to my blog

Fast Track Your Book Design and Production Knowledge While Learning About Your Book's Genre.

Download one of My Powerful Self-publishing Tools to Get You Planning like a Pro.

Calculating Your Book's Page Count From Your Manuscript.

Perfect Timing!

What's best for me?
Print-on-Demand or
Offset Printing.

Yes, Please!

I Need This!

3 free tools to get you started!

I love happy subscribers!


This free and detailed workbook exercise will fast track your book design and production knowledge and get you planning like a pro.

Ready to Self-publish Your Book But Not Sure Where to Start?

I want you to be happy with the content I deliver, so I make it easy for you to unsubscribe at any time.

I love happy subscribers!


Use this estimating page count worksheet to calculate how many pages your designed book will be.

Have a manuscript, but can't estimate how many pages your book will be?

I want you to be happy with the content I deliver, so I make it easy for you to unsubscribe at any time.

I love happy subscribers!


This free worksheet, will help point you in the right direction.

When is it best to use print-on-demand over offset printing?

I want you to be happy with the content I deliver, so I make it easy for you to unsubscribe at any time.