The maximum distance for 100Base-TX (standard ethernet cable) is 100 meters. This would be the distance from a switch to a PC, The maximum total distance between 2 devices connected to the same switch would be 200 meters.
I believe you could cascade switches together to further increase the distance, but I am unsure of the details.
If you went further than the 100 meters it is likely that you would begin to have an excessive amount of packet collisions, reducing your effective throughput.