The maximum length for a quality Cat5e or Cat6 Ethernet cable is roughly 295 feet (90 meters), with an additional 16 feet (5 meters) of patch cable allowed on each end, totaling 328 feet (100 meters).
Exceeding this distance can cause signal degradation, leading to slower speeds and reduced connection reliability.
For distances beyond this a repeater (such as network switch) will be required or to instead consider fibre optic cables.