A C# (specifically, .NET Core, though it won't work on anything but Windows) port of OneLoneCoder's C++ command line FPS demo. I tried to implement it line-by-line, as close as I could (sometimes by adding an abstraction or two).
All credit goes to https://github.com/OneLoneCoder/CommandLineFPS
Read the header of the original source here: https://github.com/OneLoneCoder/CommandLineFPS/blob/master/CommandLineFPS.cpp
tl;dr: Make sure your console is exactly sized at 120 columns x 40 rows, and preferably, use Consolas at size 16