Provided are a system and method for determining a weight of an item for purchase, comprising determining from a digital image of an item generated by a single camera a volume of the item, the single camera separated from the item at a distance in a horizontal and vertical direction established by a stationary rigid fixture; identifying the item; accessing a database to determine an average weight per volume measurement unit of the identified item; and calculating a weight of the item from the volume and the average weight per volume measurement unit.