When a professional designs the interior of a book, they make dozens of choices. This is what sets true designers apart from hobbyists—a sense of intentionality instead of making arbitrary choices. The trim size of a book may affect those design choices more than anything else. Most authors choose a trim size just because they’ve got an idea in their head of how they want their book to look, and that’s not all that bad. You can do better, though.
Before we even start, we encourage you to grab a ruler and pull a few books off of your shelves. Measure them. Get a feel for what the trim sizes we’ll be talking about actually look and feel like.
What is Trim Size?
When a book is printed, the pages are slightly larger than their final size. The content is printed, then those pages are cut down to their proper, final size. That’s the trim size.
When you have a book printed—or designed by BookFuel—you’ll have a choice of trim size. If you’re using Print on Demand technology, your choices will be constrained by the printer’s options, but thankfully there tend to be a lot of them. CreateSpace's available trim options (and corresponding page limits) are available here, for example.
What are the Most Common Trim Sizes?
The most common trade paperback sizes are 6”x9” and 5.5”x8.5” . You’ll also see 5.25”x8” and 5"x8" fairly frequently (as most Print on Demand services allow for them.) Most likely, any of those are basically fine choices for you.
Some books benefit from being larger—maybe they’re children’s books, textbooks, or photography books, for example. Common dimensions for larger sizes include 7”x10”, 8.5”x11”, and 8.25”x8.25”.
Most books either fall into the category of mass-market paperback or trade paperback.
Mass market paperbacks are 4.25”x7”, and those are the paperbacks that tend to be at supermarkets, convenience store checkout lanes, etc. These are not usually an option for self-publishers, but they’re pretty economical for big publishers when there’s a need to inexpensively print a large volume of books. Trade paperbacks tend to be standard or large-sized (often the same size as the hardcover, if it exists), and of a general higher quality than mass-market paperbacks. The vast majority of self-published books are trade paperbacks.
How Do I Choose the Right Trim Size for My Book?
If you’re having someone do your interior layout for you, you can ask them for a suggestion. Professional book designers are going to choose based in large part on the overall feel they want to create—which is going to include fonts, line spacing, and other factors. So, if they want to use a larger font, they might suggest a slightly larger trim size, too. Designers are trying to hit a certain range of lines per page and characters per line, among other things—there’s a surprising amount of science that goes into all of this, much of it having to do with the way readers’ brains work. One of the biggest mistakes self-publishers frequently make is not taking advantage of their designers’ know-how.
If you’re choosing yourself, take the following into account:
The trim size affects the final page count.
In a lot of cases, the trim size doesn't directly affect your royalties in Print on Demand systems. What does affect them is the page count, and the trim size can help lower or raise it to bring it in line with your goals.
As an example, let's compare the same book (a real book from one of our clients) in different trim sizes being printed with CreateSpace. (There's a great Royalty Calculator Tool available on their website.) Let's say our author wants to charge $9.99 a copy. Right now, at 5"x8", his book stands at 355 pages, so he makes $0.87 per book. If we were to increase his book to 6"x9" and use that extra space to increase the margins a bit and make some other design changes, we can easily bring it to down a few pages—let's say 325, just to keep it reasonable: we're talking a mere 30 pages. Now he makes $1.23 per book, a 40% increase. If we can get him down to right about 300 pages, he'll make $1.53 per book—almost double what he was making at 355 pages.
Of course, font choices, leading (line spacing), and white space will also affect your page count. And you don't want to sacrifice aesthetic quality just to increase your royalties by a few cents—make a good product, above all else. However, when balanced carefully, these are factors that can increase your royalties while still maintaining a top-notch look and feel.