Aspect Ratio Calculator
Simplify any width:height into a ratio and calculate missing dimensions instantly.
Frequently Asked Questions
What is an aspect ratio?
The proportional relationship between width and height, written like 16:9. A 1920×1080 screen and a 1280×720 video share the same 16:9 ratio at different sizes.
How is a ratio simplified?
Both numbers are divided by their greatest common divisor. 1920 and 1080 share a GCD of 120, giving 16:9.
Which ratio should I use for social media?
Use 1:1 or 4:5 for feed posts, 9:16 for stories and reels, 16:9 for YouTube, and 3:2 or 4:3 for many photo prints.
What if my ratio is not a whole number?
Some dimensions reduce to decimals (for example 2.39:1 for cinema). The tool shows the decimal form alongside the simplified integer ratio when it is not exact.
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