16:9 Aspect Ratio Calculator

Keep the 16:9 ratio while resizing width or height.

Processed locally — nothing is uploaded

About Aspect Ratio Calculator

Ratios are reduced to their simplest whole-number form, so 1920 by 1080 reports as 16:9 rather than 1920:1080. Dimensions that reduce to something awkward like 137:96 are usually a sign the source was cropped rather than scaled.

Calculate a 16:9 (or any) aspect ratio and resize either width or height while keeping the ratio locked, so images and video never look stretched. The maths runs in your browser.

An aspect ratio describes the proportional relationship between an image or screen's width and height, written as two numbers like 16:9. This calculator reduces any width×height to its simplest ratio, and — with the ratio locked — lets you change one dimension to instantly get the other, so you can resize without distortion.

It is the quick way to work out dimensions for a video export, a social banner, a print at a fixed proportion or a responsive layout. Common presets — 16:9, 4:3, 1:1 and more — are one click away, and locking one side gives you the other without arithmetic.

Learn how this works

Frequently asked questions

Why is 16:9 so widespread?

It was chosen as a compromise between the 4:3 of old television and the wider cinema formats, and it stuck — it is the shape of virtually every modern TV, monitor and YouTube video, so content made for it fits everywhere.

What are the standard 16:9 resolutions?

1920x1080 (Full HD), 2560x1440 (QHD) and 3840x2160 (4K UHD) are the common ones, with 1280x720 still used for lighter video. All divide cleanly, which is why scaling between them stays sharp.

How do I keep a ratio when resizing?

Fix one dimension and let the other follow: for 16:9, height is width multiplied by 9 and divided by 16. Setting both by hand is what produces the stretched or squashed look.

Common Use Cases

  • Working out the matching height for a video or banner width
  • Checking whether an image fits a required aspect ratio
  • Calculating dimensions for a thumbnail or embed

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