Aspect Ratio Calculator
NewCalculate the missing width or height from a known dimension and aspect ratio, with common presets.
Detected ratio
Frequently Asked Questions
How is the ratio simplified?
By dividing both the width and height by their greatest common divisor (GCD), using the Euclidean algorithm — for example, 1920×1080 reduces to 16:9 because their GCD is 120.
What's this useful for in practice?
Common cases: resizing a video or image to a smaller resolution while keeping the same proportions (so it doesn't look stretched), figuring out what height a 1280px-wide crop should be to match a 16:9 source, or checking whether a given resolution actually matches a named ratio like 21:9 ultrawide.
Does it round the calculated dimension?
Yes — the calculated width or height is rounded to the nearest whole pixel, since fractional pixel dimensions aren't meaningful for most image/video output.
Why is the decimal ratio (like 1.7778) shown alongside the simplified fraction?
Some software (especially video editing and camera specs) reports aspect ratio as a decimal rather than a fraction, so both formats are shown to match whichever convention you need.
Can I use this for print sizes instead of screen resolutions?
Yes — the math is unit-agnostic. Enter dimensions in inches, centimeters, or any consistent unit, and the ratio and calculated dimension will scale the same way.