Why does the ratio get reduced to '8:5' instead of '16:10'?

The tool divides both sides by the greatest common divisor — 16:10 and 8:5 are the same shape. Both are correct.

Which separators does the ratio input accept?

`:`, `×`, `x`, and `/` — `16:9`, `16×9`, `16x9`, `16/9` all work.

What does 'fit inside' compute?

Given a container W × H and your aspect ratio, the largest dimensions of that ratio that fit inside without cropping or stretching.

Yes — `2.39:1` (cinema scope) is parsed correctly.

Aspect Ratio Calculator

Convert

Three linked fields: width, height, and ratio. Type a new width and the height updates to keep the ratio; type a new ratio (`16:9`, `21×9`, `1920/1080`) and the height adjusts to match. Eight common presets cover most video/social formats. The 'fit inside' section solves the other common question: 'I have a 1280×800 container — how big will my 16:9 video render?'

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Presets

WidthHeightRatio

Result

1920 × 108016:9

Fit inside container

Largest size of this ratio that fits in the container without cropping.

WidthHeight

Scaled to: 1280 × 720

How to use

Pick a preset, or type any width/height/ratio — the others update automatically.
Optionally enter a container size to see the scaled-to-fit dimensions.
Copy the result string.

Frequently asked questions

Why does the ratio get reduced to '8:5' instead of '16:10'?: The tool divides both sides by the greatest common divisor — 16:10 and 8:5 are the same shape. Both are correct.
Which separators does the ratio input accept?: `:`, `×`, `x`, and `/` — `16:9`, `16×9`, `16x9`, `16/9` all work.
What does 'fit inside' compute?: Given a container W × H and your aspect ratio, the largest dimensions of that ratio that fit inside without cropping or stretching.
Decimals?: Yes — `2.39:1` (cinema scope) is parsed correctly.