Sales Tax Calculator

How to use this calculator

Pick a mode first. Choose Add sales tax when you have a pre-tax price and want to know the final total a customer pays. Choose Remove sales tax when you already have a tax-inclusive total — say, a receipt or a gross figure — and need to back out the pre-tax amount. Then enter the dollar amount and your sales tax rate. The result updates instantly: the big number is your answer, and the smaller figures break down the tax, the other side of the calculation, and the rate you used.

How this is calculated

Adding tax is straightforward: multiply the price by the rate to get the tax, then add it on. So $100 at 7.25% gives $7.25 of tax and a $107.25 total. Removing tax is the part people get wrong. You cannot simply subtract 7.25% from the total, because the original tax was charged on the smaller pre-tax price, not on the inclusive total. Instead you divide by (1 + rate). A $100 total at 7.25% breaks down to $100 ÷ 1.0725 ≈ $93.24 pre-tax, leaving about $6.76 of tax. Dividing reverses the multiplication exactly, which subtracting never does.

Educational estimate, not tax advice — see our disclaimer.

A worked example

Suppose you are buying a $250 chair in a state with an 8% combined sales tax rate. In add mode, the tax is $250 × 0.08 = $20, so you hand over $270 at the register. Now flip it: a colleague tells you they paid $270 for the same chair and you want to confirm the pre-tax price. In remove mode, divide $270 ÷ 1.08 = $250, with the remaining $20 being tax. The two modes are mirror images — one builds the total up, the other peels it back apart.

Why sales tax varies so much

There is no single national sales tax in the United States. Each state sets its own rate, and counties and cities frequently add local taxes on top, so the combined rate on the same purchase can differ from one zip code to the next. A handful of states levy no statewide sales tax at all, while others push well into double digits once local add-ons are included. Some items — groceries, prescriptions, clothing — may be taxed at a reduced rate or exempted entirely depending on where you are. Because of all this, always use the actual rate for the location of the sale rather than a national average.

Related tools

Outside the US, a value-added tax works on similar add-and-remove logic; our VAT calculator handles that. If you are pricing a sale item, pair this with the discount calculator to apply the markdown first and then add tax to the reduced price.