["American Journal of Biological Anthropology, Volume 190, Issue 1, May 2026. ", "\nABSTRACT\n\nObjectives\nBody surface area (BSA) and body volume (BV) are crucial for understanding variations in body size and shape in humans. Direct measurement of BSA and BV is challenging due to the complex human body shape and variation in body proportion and composition among humans. To address these limitations, we developed a multisegment model for estimating BSA and BV.\n\n\nMaterials and Methods\nThe multisegment model of the human body divides the body into eight segments, each represented by geometric solids determined by linear dimensions. The trunk segment was represented as a circular base cylinder, an elliptical base cylinder, and a cuboid to determine the most accurate trunk representation. BSA and BV were computed by summing the surface areas and volumes of these geometric solids. The estimation error of our multisegment model and the previous models was tested using 60 3D whole‐body scans of males.\n\n\nResults\nModels with circular and cuboidal trunk shapes provide more accurate BSA estimates compared to the elliptical trunk model, while the cuboidal trunk model was the most accurate for BV estimation. Our cuboidal trunk model showed a similar estimation error for BSA but reduced the error for BV estimates by at least 5 percentage points compared to previously published models.\n\n\nDiscussion\nOur model stresses the importance of accurate representation of the trunk segment with three different representations. The estimate of BSA has better accuracy than the BV estimate. The model's overall accuracy highlights its potential for broader applications in anthropological and physiological research.\n\n"]