Abstract: A computer-implemented method and system involve using a mobile smart phone to capture an image of a person for whom sizing dimensions are desired. A known dimension of the person or a reference target is included in the image. The image is processed by one or more servers. A scaling ratio can be determined from the known dimension and a pixel map of the image in which the item with the known dimension is identified. That scaling ratio may be used to determine nominal dimensions of desired portions of the person based on their pixel dimensions. For the girth dimensions, a matrix of pixel measurements of certain body portions may be used with a regression-derived formula developed from empirical data to accurately estimate the girth dimension at the chest or waist or other locations. Other methods and systems are disclosed.