What width is 1200 tall at 16:9?

1200 x 16 / 9 = 2133px. Use aspect-ratio: 16 / 9.

How to keep 1200 tall from stretching?

Set height: 1200px paired with the computed width, and aspect-ratio: W / H on the container; use object-fit for inner media.

1200 at this size works vertical or horizontal depending on ratio - check the table for portrait inversions like 9:16.

A 1200px-tall frame is used in many layouts. The table below lists the exact partner width at every ratio RatioCalc supports.

Ratio	Width for 1200	Pair	CSS
16:9	2133px	2133x1200	aspect-ratio: 16 / 9
4:3	1600px	1600x1200	aspect-ratio: 4 / 3
1:1	1200px	1200x1200	aspect-ratio: 1 / 1
9:16	675px	675x1200	aspect-ratio: 9 / 16
21:9	2800px	2800x1200	aspect-ratio: 21 / 9
3:2	1800px	1800x1200	aspect-ratio: 3 / 2
16:10	1920px	1920x1200	aspect-ratio: 16 / 10
4:5	960px	960x1200	aspect-ratio: 4 / 5
2:1	2400px	2400x1200	aspect-ratio: 2 / 1
239:100	2868px	2868x1200	aspect-ratio: 239 / 100
32:9	4267px	4267x1200	aspect-ratio: 32 / 9
5:4	1500px	1500x1200	aspect-ratio: 5 / 4
2:3	800px	800x1200	aspect-ratio: 2 / 3
18:9	2400px	2400x1200	aspect-ratio: 18 / 9
5:3	2000px	2000x1200	aspect-ratio: 5 / 3
1:2	600px	600x1200	aspect-ratio: 1 / 2

width = 1200 x rw / rh

// e.g. 9:16 at 1200 tall is 675px

Print tip: at 1200px, verify with w = 1200 x rw / rh before print - 1px matters on narrow banners.