Add a calculator to your product pages to calculate the product quantity required by square footage and more. Sell Objects Priced by Unit or Allow Customers to Add Quantities of Their Own with Measurement Price Calculator. While selling t-shirts or cell phone covers is easy with WooCommerce, many of us also sell products that aren't sold in quantities of "1", such as flooring, wallpaper, or more. The Measurement Price Calculator for WooCommerce will solve the problems you've probably encountered in setting up and pricing these products.