What is the best size for custom banner?

[Moraslovania]

I'm just wondering what is the best size for custom banners so I can make it that size. If it was asked before, I couldn't find it, because search tool is glitched out for me

I'm sorry if:
This has been asked before/ it's asked in the wrong place/ the question is stupid.

[Cosmopolitan borovan]

The width should be twice as much as the height

[Sodoran Alesia]

The width should be twice as much as the height

Really? I always thought with custom banners the width had to be 3 or 4 times the height.

[Cosmopolitan borovan]

The width should be twice as much as the height

Really? I always thought with custom banners the width had to be 3 or 4 times the height.

My mistake it's four.

[Almonaster Nuevo]

Most of the NS ones are 1200 x 300. I've also seen 1600 x 400. The main thing is the 4:1 aspect ratio.

[Jakker]

This seems better suited for Technical.

[Aclion]

1:4 is ideal, but just as important you want the subject to be as close to the center(vertical axis) as possible, because that's the part that shows up regardless of screen size. Bonus points if nothing is on the left end, where the flag will cover it.