Aspect Ratio Calculator
Simplify a width and height down to its aspect ratio, or lock a common ratio and calculate the missing width or height.
Simplified ratio
16:9
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How to use aspect ratio calculator
- 1Enter a width and height to see the simplified ratio.
- 2Or pick a common ratio to lock it, then edit either dimension — the other updates automatically.
- 3Click Unlock to go back to freely editing both dimensions.
About this tool
An aspect ratio is a width-to-height relationship simplified to its smallest whole-number form — 1920×1080 and 1280×720 are both 16:9, for example, since they simplify to the same ratio. This is useful when resizing images, videos or design layouts and you need to know exactly what dimensions preserve the original proportions.
Locking a ratio turns the calculator around: instead of simplifying two known dimensions, you fix the ratio and let the tool solve for whichever dimension you're missing.
Frequently asked questions
Both numbers are divided by their greatest common divisor — the largest number that divides evenly into both — which is the same math behind simplifying a fraction, applied to width and height.
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