What Trim Size Should You Choose for Your Children’s Book?
By Kezzia Crossley
When you're self-publishing a children's book, one of the first production questions you'll face is: What size should it be? The answer depends on your story, your illustrations, and your publishing platform.
What Is Trim Size?
Trim size is the final size of your printed book once it's been cut down (or “trimmed”) during the printing process. For example, 8.5" × 8.5" or 8" × 10".
Most Common Trim Sizes for Children’s Picture Books
Here are some industry favorites:
8.5″ × 8.5″ – A perfect square; great for a balanced, modern look.
8″ × 10″ – A classic portrait style, ideal for vertical illustrations.
10″ × 8″ – A landscape format, often used for bedtime stories and calm pacing.
7″ × 10″ or 6″ × 9″ – Less common for picture books, but sometimes used for early readers.
Keep in mind: trim size can affect printing cost, layout design, and how your book appears on a shelf.
How Trim Size Affects Illustration
The trim size you choose directly impacts how your illustrations are composed. A square format invites centered scenes. A vertical format gives you space for tall characters or storytelling down the page. A landscape layout offers breathing room and wide scenic spreads.
That’s why it’s best to choose your trim size before the illustration process begins.
Trim Size Tips for Self-Publishers
Check your platform: KDP and IngramSpark offer different trim size options.
Think about printing costs: Uncommon sizes or large formats can be pricier.
Match your story: A gentle bedtime story might benefit from wide, calm layouts, while a quirky character-driven story may work well in portrait.
The Painted Acorn Perspective
At The Painted Acorn, I help indie authors choose the best trim size for their story and design needs—before a single spread is illustrated. It’s part of making sure your book feels intentional, professional, and beautifully balanced from start to finish.
Kezzia Crossley is a Canadian illustrator and independent publishing partner behind The Painted Acorn. She helps self-publishing children’s book authors bring their stories to life with heartfelt illustrations, thoughtful layout, and handcrafted book design. Learn more at thepaintedacorn.ca