Understanding Trim Size

What trim size should I use

Are you asking yourself, “What trim size should I use for my self-published book?” If you haven’t begun thinking about it yet, it’s never too early to start! Something we’ve seen somewhat frequently among our first-time clients is that they don’t decide on a trim size early enough in the game. (As a side note, if your cover designer or formatter does not inquire about trim size, that’s not a good sign. This is crucial information they should be asking about. Books come in many different sizes, and cover and interior files must be built to specifically fit the size you’ve chosen.)

Here’s a crash course on trim size so you’ll be prepared with a plan before you reach the cover design and formatting stage!

What Is Trim Size?

Trim size refers to the width and height of your hardcover or paperback book. It is the size to which the printing company will trim your cover and pages. It is expressed with two numbers (Ex. 6×9”). Trim size doesn’t include the width of the spine since that is determined by page count. (More on that later.)


The exact sizes available to you will vary by what printer you intend to use. Be sure to locate a list of the sizes offered by your printing company and decide on one prior to formatting and cover designing. Common sizes include 5×8, 5.5×8, 6×9, 8×10, and 8.5×11. There are often more unusual sizes, too, such as 8.25×8.25 or 8.25×6.

Note that most printers offer at least a choice between white and cream paper. The paper color you choose can sometimes limit the trim sizes available to you, so do your research thoroughly. We’ve seen a few scenarios of authors only realizing their trim size wasn’t available for the cream paper they’d planned on after they’d already had a cover designed and their formatting completed!

Page Count

In the U.S., the standard page size in a Microsoft Word document is 8.5×11. Unless you are planning to use the 8.5×11 trim size when you publish, it’s important to realize that the page count you see when you type out your story or export it from Scrivener is much lower than it will be once formatted. This is simply because you can fit a lot more words on a large page than on a small one. For example, if your trim size is 5.5×8.5 (exactly half of 8.5×11), your formatted page count will likely be around double the size of your manuscript’s page count.

You can use this to your advantage as we’ll discuss in a minute.

Choosing a Trim Size

So how should you decide which trim size to use for your book? There are several things to consider:

-Genre & Audience




Did you know it’s possible to somewhat confuse potential readers by choosing the wrong trim size? Have you ever seen a 300-page historical romance as big as 8×10”? No, novels are typically on the smaller end—mass market novels are 4.25×7. Conversely, if your book is a picture book for children, readers will be expecting a large trim size rather than something small like 5×8.

If you’re wondering what size best fits your genre and audience, go to your bookshelf or to a bookstore and start measuring the covers of books similar to yours. You’ll get a feel for what various sizes look and feel like, and which are most common for your genre.


An often overlooked, but helpful thing to consider when picking a trim size is your book’s word count. Imagine you’ve written a 50,000-word novel and you decide to spread it over 8.5×11 pages. Your page count will be significantly lower than if you spread 50,000 over 5×8 pages. (You’ll even notice a difference between 5×8 and 6×9!)

Why does this matter? Because page count equals spine width.

Your 50,000 words will look and feel more like the substantial novel that they are if the spine is wider. Psychology aside, if the spine is too narrow, you actually won’t be able to put text on it! I often recommend to formatting clients that they go with something like 5×8 for their novels under 100,000 words. If the book is over 100,000 words, going up to 6×9 often looks more proportionate.


Printers usually calculate the printing cost of your book based on the number of pages. If you are on a strict budget, you may want to increase the trim size, making more space on each page and thereby decreasing the number of pages needed overall. Most printing companies will have some type of online cost calculator you can use to estimate the cost of producing your book at various trim sizes and page counts. (If you’re not sure who to use for printing your book, check out point #3 in this post!)

If you get a beautifully proportioned book but the page count and thus production cost is too high, you may have to set your book’s list price higher than you planned which could effect sales. That’s why it’s good to run the numbers prior to making your final decision on trim size. It’s the self-publisher’s version of “measure twice, cut once.”

Overall, choosing a trim size is an important, but fairly easy task. Grab a measuring tape or ruler and go book shopping! You’ll quickly get a feel for the perfect size for YOUR book.

What trim size should I use? Understanding trim size when self-publishing paperback or hardcover books.

Have a question about trim size? Ask in the comments!

2 thoughts on “Understanding Trim Size

  1. Thanks so much for the insightful post Perry! I didn’t really know much about trim size and I found this to be really helpful. I am planning on going for the 5 by 8 trim size so we will see what happens!

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