Book Sizes: How to Choose the Right One for Your Book

authors header image

Explore Author Services

You probably understand the importance of a good book cover design. However, many authors don’t consider carefully the dimensions of their book even though it’s a crucial part of the publishing process. After all, you want to make sure your book is as readable as possible. A thick one that is too small will be cumbersome to read, and a thin one that is too short will appear too flimsy to potential readers. 

We’re going to break down the most popular book dimensions and how to choose the right size for your book.

Color and resolution

Before deciding on the book cover dimensions, you need to ensure your cover looks as good as possible. Use a resolution of 300 DPI (dots per square inch) for a clear image and a CMYK (cyan, magenta, yellow, and key) color model. You want to make sure your cover is attractive as this will appeal to your readers. Even though we are often told not to judge a book by its cover, many readers do, and they may walk away from one simply because of its uninspiring cover. 

eBook covers

Most e-readers have an aspect ratio of 1.33:1, but exact dimensions aren’t necessary since the cover image will be centered and not perfectly fitted to the screen. More important than the cover image on the e-reader are the thumbnails that appear on digital storefronts.

On the Amazon store, you can upload a variety of cover sizes, but the platform recommends an aspect ratio of 1.6:1 (2600 by 1600 pixels), which is the ratio of a mass-market paperback. However, most publishers use a 1.5:1 aspect ratio (2500 by 3750 pixels) for book covers on Amazon. This is the ratio of hardcover books, and it looks more substantial as a thumbnail.

Illustrated books and cookbooks should use an aspect ratio of 1.4:1 (1800 by 3920 pixels) or 1.2:1 (3000 by 3600 pixels).

Audiobooks should use an aspect ratio of 1:1 (3200 by 3200 pixels).

Printed book dimensions

Trim size

For physical books, you will need to choose a trim size, that is, the height and width of the book. The main considerations in this choice are the cost (based mostly on page count) and the aesthetic. 

A book with larger dimensions will have fewer pages and may be less expensive, but you must think about how it will look to potential readers. With a short book, you may want a smaller trim size to ensure it doesn't appear to lack substance. If, however, your book is long, then you should consider a bigger trim so it’s not too thick and intimidating. 

Though creativity is crucial for writing a book, when it comes to choosing the right size for it, you don’t want to think outside the box. Industry standards for book sizes exist for a reason, and it is best to adhere to them. You want your book to be as sleek and professional as possible, so make sure you understand the standard size of books in your specific genre. 

Standard book sizes

The most common sizes are mass-market paperback, trade paperback, comic, and textbook.

Mass-market paperback books are 4.25” x 6.87,” and these dimensions are generally used for fiction novels.

Trade paperback books are 5” x 8” to 6” x 9,” and these dimensions are generally used for fiction and nonfiction books. Novellas are typically 5” x 8,” and hardcovers are normally 6” x 9.”

Comic books are 6.625” x 10.25.”

Textbooks are 6” x 9” to 8.5” x 11.”

How to choose a book size

The above are the standard sizes, but there is always variation. Consider what dimensions will work for the length of your book (remember cost and aesthetic), but make sure it is recognizable to its potential audience. You don’t want your book to stand out for the wrong reasons. 

For example, if your romance novel is the same size as a math textbook, readers will be confused, and you will likely lose potential sales. People will gravitate to books that look similar to what they’ve already read, so familiarize yourself with the book size conventions of the genre you write in. Even though you are self-publishing, you still want your book to be as professional and polished as possible.


Need more help getting your book to market? Check out our services for indie authors.

Explore Author Services