Calculate Any Aspect Ratio
Get the perfect dimensions for YouTube, Instagram, web design, and more. Instant calculations, no signup required.
What is an aspect ratio?
An aspect ratio is the shape of an image or screen — its width compared to its height, written as two numbers such as 16:9 or 4:5. It is independent of pixel size: a 1280×720 photo and a 1920×1080 photo are both 16:9 because both reduce to the same proportion. To simplify a resolution to its ratio, divide the width and height by their greatest common divisor — 1920 and 1080 share a GCD of 120, so 1920×1080 becomes 16:9.
Getting the ratio right is what keeps your uploads from being cropped, letterboxed with black bars, or stretched out of shape. Pick the shape for where the media will appear, then let the pixel dimensions follow.
| Ratio | Orientation | Example size | Best for |
|---|---|---|---|
| 16:9 | Landscape | 1920×1080 | Video, YouTube, screens, slides |
| 9:16 | Portrait | 1080×1920 | TikTok, Reels, Stories, Shorts |
| 1:1 | Square | 1080×1080 | Profile pictures, feed posts, album art |
| 4:5 | Portrait | 1080×1350 | Instagram feed posts |
| 4:3 | Landscape | 1024×768 | Older screens, presentations |
| 21:9 | Ultrawide | 2560×1080 | Cinematic video, ultrawide monitors |
How it works
Choose 16:9, 4:3, 1:1 or any custom ratio — or drop an image to detect its ratio.
Type a width or a height and the matching dimension appears instantly.
Copy the result or share the bookmarkable link to reopen the same calculation.
Watch how it works
A quick tour of the calculator — pick a ratio, enter one dimension, copy the result.
Perfect for
Popular aspect ratio calculators
Jump straight to the calculator that matches your format and copy the exact width or height you need.
Frequently asked questions
Learn about aspect ratios
Short, practical guides to help you choose the right proportions and sizes.
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