The technique of reciprocity calibration, which allows the absolute determination of sound quantitaties, has been effectively used for many years at low frequencies. The self‐reciprocity modification of this technique requires fewer measurements and has higher accuracy. Present day pulse echo systems have been used to perform this calibration on their own transducer. These transducers are available with wide bandwidths and can be used to measure both peak and average fields. The technique is discussed from the standpoint of energy density, from which the self‐reciprocity conditions and derived in a convenient form. The choice of auxiliary measurements of impedance or open‐circuit voltage is also discussed. No acoustical standards are required. The technique appears to be suitable for average power measurements on pulsed and CW systems. Corrections for short‐pulse operation of typical medical systems require further investigation.