Aspect Ratio Calculator
Pick a ratio or enter custom width/height to get exact pixel dimensions for AI image generation, wallpapers, print and social media — plus a ready-to-copy Midjourney --ar parameter.
--ar 1:1
AI generation sizes
Wallpaper sizes
Print sizes (300 DPI)
Social media sizes reference
Sizes used across major platforms, for context when picking your ratio:
| Platform & placement | Recommended size | Ratio |
|---|---|---|
| Instagram feed post (square) | 1080 × 1080 | 1:1 |
| Instagram portrait post | 1080 × 1350 | 4:5 |
| Instagram / TikTok Story or Reel | 1080 × 1920 | 9:16 |
| YouTube thumbnail | 1280 × 720 | 16:9 |
| Facebook shared image | 1200 × 630 | 1.91:1 |
| X (Twitter) post image | 1600 × 900 | 16:9 |
| LinkedIn post image | 1200 × 627 | 1.91:1 |
| Pinterest Pin | 1000 × 1500 | 2:3 |
How the Aspect Ratio Calculator works
Choose a ratio
Pick a common preset like 16:9 or 1:1, or type in any custom width and height.
Toggle orientation
Switch between landscape and portrait to flip the ratio instantly.
Copy dimensions or --ar
Grab the exact pixel dimensions from the tables, or copy the ready-made Midjourney --ar parameter.
About this tool
Aspect ratio (the relationship between width and height) determines the shape of an image, independent of its resolution. Getting it right before you generate saves you from awkward AI-generated crops, oversized print files, or blurry social media uploads.
This calculator works two ways: pick a common preset (1:1, 16:9, 9:16, 4:5, 3:2 and more) or type in any custom width and height, and it instantly simplifies the ratio, generates the matching --ar parameter for Midjourney, and shows suggested resolutions for AI generation, desktop/phone wallpapers, and print at 300 DPI.
Every calculation happens locally in your browser as you type — there's no server round-trip, so results update instantly.
Frequently asked questions
How do I find the aspect ratio of an image?
Enter the image's width and height in pixels into the calculator above; it automatically simplifies the ratio (for example, 1920x1080 simplifies to 16:9).
How do I use the --ar parameter in Midjourney?
Add --ar followed by your ratio to the end of any Midjourney prompt, for example --ar 16:9 for a widescreen image. Use the Copy button above to grab the exact parameter for your chosen ratio.
What aspect ratio should I use for AI art?
It depends on your use case: 1:1 for a flexible square, 16:9 for widescreen/desktop, 9:16 for phone wallpapers and Stories, and 4:5 or 3:2 for portrait/photography-style compositions.
Other aspect ratio tools
Writing the prompt itself? Try the Prompt Character Counter →