Choosing among size/resolution can be a daunting task for gamers.

Most people are satisfied with 27″ screens. They are reasonably big, but not too big that you’d have to move your head from one corner of the screen to the other to catch all that’s happening on the screen.
The ideal resolution of a 27″ monitor is 2560×1440 (WQHD), which results in a pixel density of ~109 pixels per inch. You get the perfect amount of screen space and details without any scaling necessary.
In contrast, a 27″ 1080p (1920×1080 – Full HD) monitor has a pixel density of ~81 PPI, which means you get little screen real estate and pixelated picture quality, though some users don’t mind this as they’d rather have a bigger screen than clear and sharp picture quality.
These are the optimal monitor size/resolution combinations.

- 25″ or smaller: 1920×1080
- 27″-32″: 2560×1440 and 3840×2160
- 32″ or bigger: 2560×1440 and 3840×2160
- 25″-30″ ultrawide: 2560×1080
- 34″-35″ ultrawide: 3440×1440 and 5120×2160
- 38″ ultrawide: 3840×1600
- 40″ ultrawide: 5120×2160
- 43″ super-ultrawide: 3840×1200
- 49″ super-ultrawide: 5120×1440
Of course, you need to make sure that your CPU/GPU is going to be able to handle the monitor’s resolution at its maximum refresh rate which brings us to the next specification that you need to consider.