Aspect ratio calculator.
Lock a ratio, change one dimension, and the other follows. Or type any width and height to read the ratio. Handy for resizing video and images to exact specs without stretching. Runs in your browser.
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See how it worksAbout this tool
Resize while keeping the aspect ratio, or read the ratio of any width and height. Pick a common ratio like 16:9 or 9:16, change one dimension, and the other updates so nothing stretches. Everything runs in your browser.
How to use it
- Pick a common ratio, or type your own width and height.
- With "Keep ratio" on, changing the width updates the height, and the reverse, in proportion.
- Read the simplified ratio and the decimal ratio below.
Frequently asked questions
The relationship between width and height, written like 16:9. It stays the same at any pixel size, so 1920x1080 and 1280x720 are both 16:9.
16:9 for landscape and YouTube, 9:16 for Stories and Reels, 1:1 or 4:5 for the feed. Always check the current platform specs, since they change.
This only calculates the dimensions. Scaling the actual file down stays sharp; scaling up beyond the original size softens it.