21:9 Aspect Ratio

Resolutions, uses and the formula for the 21:9 aspect ratio.

21:9 aspect ratio = 2.333

Used for ultrawide monitors and cinema. Height = width × 9 ÷ 21.

Ratio

:

Size in pixels

×

Change the width or height and the other one follows the ratio. Change both to find the ratio.

Keep the ratio when I change the size Round to even numbers (recommended for video)

16:9aspect ratio

1.78as a decimal

16:9closest standard

2.07megapixels

1920 × 1080

Common 21:9 resolutions

Width × height	Megapixels

21:9 means 21 units wide for 9 units high. It is used for ultrawide monitors and cinema. As a decimal, the width is 2.333 times the height.

From a width: height = width × 9 ÷ 21.
From a height: width = height × 21 ÷ 9.
Round to even numbers for video.
Changing the ratio of an image means cropping it or adding bars: resizing alone would stretch it.

Popular resolutions:

Updated October 2026.

What resolutions are 21:9?

Common ones: .

What is 21:9 used for?

It is used for ultrawide monitors and cinema.

How do I calculate a 21:9 size?

Height = width × 9 ÷ 21. Width = height × 21 ÷ 9. Or type one side in the calculator above.