Category 6 (Cat 6) cable is a standardized twisted pair cable used for Ethernet and other network physical layers, designed to be backward compatible with Category 5/5e and Category 3 standards.

Cat 6 cables adhere to stricter requirements for crosstalk and system noise compared to Cat 5 and Cat 5e, offering performance up to 250 MHz—significantly higher than the 100 MHz limit of its predecessors.

While Cat 6 cables have a reduced maximum length of 55 meters for 10GBASE-T applications, the enhanced Category 6A (Cat 6A) version supports frequencies up to 500 MHz and features improved alien crosstalk resistance, enabling 10GBASE-T transmission over the full 100-meter (330 ft) distance supported by earlier Ethernet standards.

For 10/100/1000BASE-T applications, the maximum permitted length of a Cat 6 cable is 100 meters. This includes a 90-meter permanent link—typically solid horizontal cabling connecting two points, such as a patch panel and a wall jack—and an additional 10 meters of stranded patch cords. Some manufacturers now claim their Cat 6 cables can support distances exceeding 100 meters, though such lengths fall outside the TIA 568–2.D standard.