Team Fortress 2 doesn’t always run in the correct resolution. Sometimes it’s only a little bit off but other times, it can be drastically low even though you have a screen that supports better, higher resolutions. If that’s the case, you can use a simple little trick to run Team Fortress 2 in the correct resolution.
Fix Team Fortress 2 resolution
Open Steam and go to your Library. Look for Team Fortress 2 in the list of games (it should be installed) and right-click it. From the context menu, select Properties.
On the Properties window, go to the General tab and click the ‘Set Launch Options’ button. Another window will open. In this window, you can enter simple arguments that tell the game how to run.
To change the resolution that the game runs in, enter the following.
-windowed -w Screen-Width -h Screen-height
-windowed -w 1920 -h 1080
If you’re not sure what your screen resolution is, you can check from the Settings app. Open the Settings app and go to the System group of settings. Select Display and look at the value under ‘Display Resolution’. The first value is the ‘width’ and the second is the ‘height’.
The command given above will run the game in windowed mode. If you don’t want the app to run in windowed mode, you can skip the -windowed part.
This will work for other games too and there are other commands you can enter in the launch options. You can also use it to run a game with a specific version of DirectX for example, you can use -dxlevel 90 if you want to run a game with DirectX v9.0. The difference between this command and the resolution one is that some games may not be able to run with the version of DirectX that you enter in which case, the game will fail to launch. Before using a command-line switch like this on a game, make sure that the game itself is compatible with it.
As for why Team Fortress 2 runs with the incorrect resolution, it’s hard to say. You can check the game’s settings and see if you’ve set the correct resolution in the game itself. Go to the game’s settings and select the Video tab. There’s a dedicated dropdown for the resolution. Pick the ‘Native’ option which will match your screen’s current resolution.
This is anecdotal but, after using the launch option to run the game, it began to run in the correct resolution even after I removed the modified launch option.