Typical USB cables are 1 meter, or approximately 3 feet, in length, not including the length of the USB connectors. The maximum cable length allowed under USB 2.0 specifications is 5 meters.
Maximum cable length restrictions prevent potential damage to USB components from the power levels required to send signals and power over longer cables. Designers did not intend for the USB specification to transmit data over long distances, unlike the Ethernet cable protocol, which has a maximum cable length of up to 90 meters. However, it is possible to use USB hubs to extend the maximum distance of a USB connection past the maximum cable length.