It depends mostly on the resolution. A 24-inch monitor is good for 1080p and 27-inch monitors are good for 1440p and 4K.
Wondering what the best monitor size for gaming is? Well, it depends on the resolution you’re seeking. Nowadays, 1080p is not enough and will not hold for the future, so you will need to invest in either a 1440p monitor or 4K Ultra HD monitor.
Generally, most gamers use a 24-inch monitor, but you might like a 27-inch better if you have the budget and space for it. They’re better suited for 1440p and 4K UHD, which is what you want if you want to buy a new gaming monitor.
A gaming monitor is something you don’t replace quite so often, so be sure to make a good pick or otherwise you’re going to regret it.
Therefore, our official recommendation is that you get a 27-inch monitor with either 1440p or 4K UHD resolution. Do not get a 27-inch monitor with 1080p resolution and likewise do not get a 24-inch monitor with 1440p resolution, 4K is best for 28-inches to 30 inches. 32-inch and higher is too high for a gaming monitor.
For a brief overview of our recommendations, see the list below:
23-inch: Not recommended
24-inch: 1080p (fine choice, but won’t hold for the future)
25-inch: 1080p (like the one above, not recommended because of 1080p and we do not recommend 1440p or higher on a 24-inch or 25-inch monitor)