Aspect Ratios for Phone/Computer Game?

So i want to make a phone game but also work on PC. I am gonna have the 16:9 (1920x1080) ratio which is really easy to create in photoshop but how many pixels would it be for the mobile version which will be in the middle? I know it’s not efficient but ill work on it later .

Here are some examples of what I mean: (In the middle is where i want the main game screen to be)
http://bit.ly/2fcl3hC

There is no single answer to how wide the middle should be, as there are many screen sizes and aspect ratios, but most probably you’ll want a middle area of 9:16 (w:h) as this is most common (see Unity mobile hardware statistics).

The actual pixel width of the middle is depending on the resolution of the desktop monitor the game is played on - there are quite some variations out there, you’ll want to keep in mind other aspect ratios than 16:9 screens.

@jorrit5477 My screen is 1366 x 768 so a normal 16:9 screen. I have added a 1920 x 1080 background image in the Unity Scene. So i just need to make a 9:16 screen. Alright i’ll work on that. Thanks!