Abstract: A digital ultrasonic extensometer for measuring the stress in a tensile load member, such as a bolt under load, the extensometer including a transducer permanently or temporarily in contact with the load member being measured, an intelligent processing means controlled time interval measuring means which generate a number of signals for energizing the transducer, the transducer, in turn, receiving the return pulse from the far end of the member under test and converting it into an electrical signal which is amplified and provided to the digital circuitry; the time interval measuring means then measure the number of clock pulses and portions of clock pulses during the period of time from the pulser signal to the receipt of the signal return from the end of the test member, provide a plurality of such pulse groups to the intelligent processing means, which enhance the accuracy of measurement by computational averaging computing, and indicate on a digital display and on an included paper printer, the computed in