While there are many AI tools for image generation, MidJourney stands out. It lets you create images in any aspect ratio; making it a perfect illustrator for KDP’s coloring books, children’s books, graphic novels, short stories, and other image book publications.
If you have tried to create books for kdp with AI, you’ve probably bumped into the aspect ratio issue. Getting the aspect ratio right makes editing and formatting easier. Plus, your images will look fantastic in your book.
In this article, I’ll break down how to figure out the correct aspect ratio for your book. And how you can calculate it for seamless Amazon uploads.
What is aspect ratio?
The term aspect ratio refers to how the height and width of an image relate to each other. We usually express it in whole or fractional numbers, separated by a colon.
While MidJourney allows you to use almost any aspect ratio, you cannot include fractions; only whole numbers.
If you want to change the aspect ratio in midjourney, you need to add the text “‐‐ar width:height for example ‐‐ar 2:3” at the end of your prompt. By default, the midjourney bot creates images with 1:1 aspect ratio; which is not suitable for most kdp book sizes.
Important notice
In kdp, the aspect ratio is not affected by bleed or margins. The Bleed is that extra space outside and the margin is the inner safe space. So, whether you choose to add bleed or not to your kdp book, it doesn’t change the book’s aspect ratio.
If you are creating ebooks, the aspect ratio is not really important. The dimensions you use for your ai ebook images all depend on the design and it’s not limiting like the print books.
The aspect ratio for 8.5 inches by 11 inches book
This is a tricky one. According to industry standards, the aspect ratio for 8.5×11 is 1:1.29. This is a no-go in MidJourney because it does not accept fractions.
So, what’s the workaround? From my digging around, I found a neat trick. Just take the book size in inches and multiply each dimension by 10.
For an 8.5×11 kdp book, the aspect ratio is 85:110
For example, you need to add the text below at the end of your prompt.
--ar 85:110
I’ve tried other aspect ratios, but this one really does the trick. It’s not an exact fit as you will have a bit extra. But it works great for most 8.5 by 11 inches books. I have published several large print coloring books using this aspect ratio and I had no issues uploading my manuscripts.
Other kdp book size aspect ratios
The table below shows a breakdown of the standard KDP book sizes and their respective aspect ratios using the multiplying method.
Remember, KDP lets you choose custom book sizes. But for low and medium-content books, sticking to standard sizes is your best bet. Also, some book sizes can use the default midjourney square aspect ratios as you can see below:
| Kdp book sizes | Midjourney Aspect ratios |
|---|---|
| 8.5 x 11 | 85:110 |
| 8 x10 | 80:100 |
| 8.25 x 8.25 | 1:1 |
| 5.5 x 8.5 | 55:85 |
| 6 x 9 | 60:90 |
| 7 x 10 | 70:100 |
| 8.5 x 8.5 | 1:1 |
| 5 x 8 | 50:80 |
Wrapping up
Mastering the aspect ratio sizing skills for KDP books, especially with AI tools like MidJourney, can be a game changer. Remember, the right aspect ratio can make your book images stand out in quality and appeal.
Hi, I’m Blessing, a pro writer and graphic designer turned AI EXPERT! My passion is helping you unlock the full potential of AI tools to elevate your skills and create a successful side hustle or brand.
I skip the hype and focus on what truly works, bringing you the best tools to 10x your creativity.