Midjourney Size Prompts: A Simple Guide to Getting the Right Image Dimensions
When you're creating visuals with AI, especially in Midjourney, getting the right size prompt can make all the difference. Whether you're designing for Instagram, a website banner, or product packaging, the way you set up your Midjourney prompt size will impact how your image looks and fits into your brand’s world.
What Are Size Prompts in Midjourney?
When you create an image in Midjourney, by default, it gives you a square (1:1 ratio). But what if you need a wide landscape for a website header? Or a tall image for Pinterest?
That’s where Midjourney aspect ratio prompts come in.
You can adjust the aspect ratio by adding --ar (short for aspect ratio) to your prompt.
Easy Size Prompt Examples
Here are some helpful formats you can use in your prompt:
Platform / Use Aspect Ratio/ Prompt Example
Instagram Post / 1:1 / a cozy home workspace --ar 1:1
Instagram Story / 9:16 / a calming skincare flatlay --ar 9:16
Website Banner / 16:9 / modern wellness brand header --ar 16:9
Pinterest Pin / 2:3f/ feminine brand moodboard --ar 2:3
Tips for Using Midjourney Prompt Sizes
Always add your aspect ratio at the end of the prompt. For example:
” a creative female entrepreneur with a camera, soft natural light --ar 4:5”
Match the format to your platform. Think about where the image will be used — different platforms look best with different shapes.
Keep experimenting! Sometimes small changes in ratio can make a big visual difference.
Why Size Prompts Matter
Using the right Midjourney size prompt helps your image look professional and intentional. No more awkward crops or stretched photos. And if you’re building a cohesive brand, size really does matter.
A Quick Personal Note
When I first started using Midjourney, I was amazed by the image quality, but totally confused by the sizing. My first few images looked great until I tried to post them on Instagram… and they just didn’t fit. That’s when I started experimenting with size prompts and aspect ratios. It took a bit of trial and error, but once I got the hang of it, everything clicked. Now I use size prompts on every image, and I teach my clients how to do the same. It's a small tweak that makes a huge difference in the final results.
Need Help With Prompts?
If you're not sure which size to use or how to get the best results, that’s what I’m here for! My studio helps you create stunning, AI-generated visuals that are 100% on-brand, and I’ll teach you how to do it, too.
Check out my Visuals & Prompt Packs or Contact Me to get started!