Sales Tax Calculator – Add Tax, Remove It and Check Your Receipt
A price tag rarely tells you what you will pay at the till. This sales tax calculator adds tax to a price, takes it back out of a total, checks an itemized receipt line by line and works out the rate a store charged you. It covers US sales tax with stacked state and local rates, Canadian GST, HST, PST and QST, and a custom mode for VAT or any other rate. All maths runs in whole cents, rounding half up the way most tills do.
How to calculate sales tax
Multiply the pre-tax price by the rate, then add the result: tax = price × rate and total = price + tax. Three items at 19.99 make a subtotal of 59.97. At 8.25%, the tax is 59.97 × 0.0825 = 4.947525, which rounds to 4.95, for a total of 64.92. Tax is worked out on the whole subtotal rather than per unit, which is why the price per unit (21.64) is only a rounded figure.
How state, county, city and district rates stack
In the US, the state rate is only the starting point. Counties, cities and special districts such as transit authorities add their own rates, and the combined sales tax rate is the sum. Houston is a good example: Texas charges 6.25%, the city adds 1% and the METRO transit district adds another 1%, giving the 8.25% printed on receipts. Five states (Alaska, Delaware, Montana, New Hampshire and Oregon) have no statewide sales tax, although Alaska lets local governments charge one. Local rates depend on your exact address, so the calculator asks you to type them in rather than guessing from a ZIP code.
Taking tax out of a total (and the common mistake)
To find the price before tax, divide by one plus the rate: price = total ÷ (1 + rate). For 108.25 at 8.25%, that is 108.25 ÷ 1.0825 = 100.00. The tempting shortcut of subtracting 8.25% of the total gives 99.32, which is 0.68 too low. The tax was calculated on the smaller pre-tax price, so it makes up only 7.62% of what you paid, not 8.25%.
Rounding per line or per receipt
Stores round tax either once on the whole receipt or on every line, and the two can differ. Three separate items at 2.10 with 8.25% tax give 0.52 when rounded once, but 0.51 when each 0.17325 is rounded to 0.17. Neither is wrong, so a receipt can be a cent off from a calculator. The itemized receipt tab shows both methods.
Taxable and exempt items, coupons and shipping
Many receipts mix taxable and exempt items. Groceries are exempt or taxed at a reduced rate in many states, while household goods and electronics are taxed in full. An order-level coupon is spread across the lines in proportion to their prices. A store coupon usually lowers the taxable amount, but in many states a manufacturer coupon does not. Whether shipping is taxed also varies. The calculator lets you set each of these yourself rather than encoding any one state's rules.
Canada: GST, HST, PST and QST
The federal GST is 5% everywhere in Canada. Ontario (13%) and the Atlantic provinces (14–15%) merge it with their provincial tax into a single HST. British Columbia, Manitoba and Saskatchewan charge a separate PST or RST, and Quebec charges the 9.975% QST. Each tax is calculated on the pre-tax price and printed on its own line, so on 100.00 in Quebec you pay 5.00 GST plus 9.98 QST, for 114.98.
What this calculator doesn't cover
It is a shopper's and bookkeeper's check, not a compliance tool. It doesn't look up rates by address or handle use tax, seller registration and filing, or product-specific rules for vehicles and digital goods. For Indian GST, use the GST calculator. US state rates are current as of July 2026 and are reviewed every six months.