Aspect ratio calculator

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How the ratio is worked out

The ratio is width and height divided by their greatest common divisor. 1920 × 1080 shares a divisor of 120, which leaves 16:9. Sizes that share nothing, such as 3440 × 1440 (divisor 80, leaving 43:18), stay as odd-looking numbers.

What does 1.78:1 mean?

The decimal form is the width divided by the height, written against a height of 1. 16:9 is 1.78:1, so the picture is 1.78 times as wide as it is tall. It makes ratios easy to compare: 2.39:1 is wider than 1.85:1.

Why is 3440 × 1440 called 21:9?

Real 21:9 would be 2.33:1. Panels at 3440 × 1440 and 2560 × 1080 are 2.39:1 and 2.37:1 and are sold under the rounder name. When a size is close to a common ratio but not equal to it, the result says so and gives the difference.

Why does a calculated side get rounded?

Pixels are whole. 16:9 at a width of 1279 would need a height of 719.44, so the result is 719 and the page shows both numbers. The ratio of the rounded size is then very slightly off.