This calculator works in two directions. Choose the first option when you have a price without tax and want to know what you will pay at the register. Enter the price of one item, the sales tax rate and the quantity. The tool shows the tax amount and the final total.
Choose the second option when you already have a price that includes tax, such as a receipt total, and you want to know how much of it was tax. Enter the total per item, the tax rate and the quantity, and the tool takes the tax out to show the price before tax. Business owners often need this when they check invoices or prepare records.
Many places charge more than one tax. If you pay a state or provincial rate plus a city or county rate, enter the first one in the main box and the second one in the extra box. The calculator adds them together and shows how much of the tax belongs to each part. If you buy several items at the same price, change the quantity and the tool does the multiplication for you.
To add tax: tax = price x quantity x combined rate, and total = price x quantity + tax. The combined rate is the main rate plus the local rate, both written as decimals.
To remove tax from a total: price before tax = total / (1 + combined rate), and tax = total – price before tax. Dividing is the correct way to do this. Simply taking the tax percentage off the total gives a slightly wrong answer, because the tax was calculated on the smaller price and not on the total.