ABSTRACT Introduction The objective of this effort was to develop and evaluate an algorithm that used socket and panel dimensions and cable length measurements to quantify socket volume changes of cabled-panel, adjustable socket systems. Methods Adjustable sockets were fabricated for three participants with transtibial amputation. An apparatus was constructed to measure socket volume under controlled cable length changes using the water displacement method. Socket volume calculations from the algorithm were compared with results from water displacement testing. Results For the three sockets tested, the algorithm predicted minimum socket volumes that ranged from −7.1% to −6.1% less than the neutral volume (flush panels) and maximum volumes that ranged from +1.7% to +3.6% more than the neutral volume. Root mean square error between model and experimental results for socket volumes less than the neutral volume ranged from 0.3% to 0.5% socket volume. Conclusions If the algorithm was incorporated into adjustable socket mechanisms and measured users' socket size adjustments, the data may help practitioners identify relationships between patients' clinical status and their socket volume adjustments. Data may also be useful toward the design and operation of automatically adjusting cabled-panel sockets.