Tax-Rate, Tax-Amount and Gross-Amount Calculator: This app allows you to find two common unknowns, however, you must know the retail price (Before-Tax amount): 1. If you know the Before-Tax amount and the Tax-Rate this app will provide the gross price (After-Tax amount). It will also display the amount of tax you were charged (Tax-Amount) as read-only info. 2. If you know the Before-Tax amount and the After-Tax amount, this app will calculate the Tax-Rate. Click the Clear Button to clear inputs and perform new calculations. (click to close help)