I finally got Microsoft Flight Simulator to run, and I want to figure out how badly it performs on my computer (the sim informs me every launch that my specs are sub-minimum). How can I check my framerate in the sim?
If you're playing on Steam, then as per this link, enabling the FPS option in steam before the game is opened worked for me:
Valve recently added an FPS counter to Steam’s in-game overlay. In Steam (while no games are running), just head to Steam > Settings > In-Game and then pick a position for the FPS display from the “In-game FPS counter” dropdown.