Aspect Ratio Calculator

Simplify a width and height into a clean aspect ratio like 16:9.

Result

Aspect ratio

16:9

Decimal ratio

1.778

How it works

Divide width and height by their greatest common divisor

An aspect ratio expresses the relationship between width and height in its simplest whole-number form. This calculator divides both dimensions by their greatest common divisor: 1920 × 1080 has a GCD of 120, giving 16:9. A handful of ratios dominate screens and images. 16:9 is the standard for televisions, monitors and YouTube; 4:3 is the older television and tablet shape; 21:9 is ultrawide cinema; 1:1 is the square of social feeds; and 9:16 is vertical video for phones. Because the ratio is a proportion, resizing does not change it: 1920×1080 and 1280×720 are both 16:9. That is exactly why it matters — respect the ratio when you resize and the image stays intact; ignore it and you get stretched faces or black bars added to fill the gap.

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Frequently asked questions

What is a 16:9 ratio?

A widescreen shape: 16 units wide for every 9 tall — the standard for TVs, monitors and video.

Does resizing change the ratio?

No — scaling keeps the same ratio as long as width and height grow by the same factor.

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