If you don't figure out sales tax before making a purchase, you may be unpleasantly surprised by how much more an item costs when the sales tax is added to it. Learning how to easily calculate sales tax will help avoid such situations. The process requires only an awareness of the sales tax in the state in which you are shopping and basic multiplication, which may be accomplished with or without a calculator
Identify the sales tax rate. Be aware that some counties and municipalities add local taxes on top of the state's basic sales tax. You must calculate those taxes separately.
Multiply the price of the item by the state sales tax and then divide that by a hundred. For example, if an item costs $50, and the state sales tax is 6.5 percent, then the sales tax on this item will be $3.25. 50 x 6.5 / 100 = 3.25
Add the sales tax to the listed price to determine the total. The item is this example would cost $53.25. 50 + 3.25 = 53.25