Many procedures have been described for calibrating a 6-port reflectometer. Some of these require externally switched components such as phase shifters or attenuators. These complications are avoided in the 5-standard calibration technique described, which needs only two airlines in association with short circuits and open circuits. The use of a matched load standard is also avoided, because those commercially available are not good enough for that purpose. The new technique is considered to be a significant improvement on the previously published method requiring seven standards, comprising five modulus-1 standards and two others having a modulus considerably less than unity.