Abstract: An apparel item sizing process for ascertaining best fitting apparel items from a plurality of product offerings, the process includes collecting apparel item details by inputting into an electronic database apparel item details for a plurality of brand manufacturers or retailer. The process further includes the apparel item details of at least one item type, brand name, brand line, pricing, dimensions, color, potential popularity based on reviews, location, and ratings. The process utilizes an computational analysis system to determine a closeness of fit score of one or more apparel items of interest to a reference apparel item utilizing the collected apparel item details. The reference apparel item is an item known to fit a customer based upon prior experience and the closeness of fit score is derived from a formula utilizing at least one critical dimension that is key to the satisfaction of the customer.