Sales Tax Calculator
Free sales tax calculator: add tax to a pre-tax price, or back the tax out of a tax-included total, using your local combined rate.
Last reviewed: July 2026Quick Answer
To add sales tax, multiply the pre-tax price by your combined rate and add it back: $47.50 at 8.25% is $3.92 in tax, for a $51.42 total. To remove tax from a tax-included total, divide the total by 1 plus the rate — not subtract the rate — to recover the original price.
What This Sales Tax Calculator Does
This sales tax calculator works out the tax added at the register on a purchase. Give it a price and your combined sales-tax rate and it returns the sales tax and the final total in add mode, or it recovers the original pre-tax price from a tax-included total in remove mode. Sales tax is a state and local tax on the sale of goods and some services, collected by the seller at checkout. It is a completely different tax from federal income tax. If you are trying to estimate what you owe the IRS on your earnings, use the federal tax estimator instead. This tool only deals with the tax on a single purchase, not your annual return.
How to Use It
Enter the amount and your combined tax rate, then pick a mode. In add mode the amount is treated as the pre-tax price: the calculator multiplies it by the rate, shows the sales tax, and adds the two together for the total. In remove mode the amount is treated as a tax-included total: the calculator divides it by one plus the rate to recover the pre-tax price, and the difference is the tax that was already baked in. The results update as you type, and the share link at the bottom saves your amount, rate, and mode so you can send or bookmark the exact calculation.
Worked Examples
A few concrete examples show both modes at work:
- Adding tax. A $47.50 item at an 8.25% combined rate has 47.50 × 0.0825 = $3.92 in sales tax (3.91875 before rounding), for a $51.42 total.
- Removing tax. A $107.00 receipt total at a 7% rate came from a $100.00 pre-tax price, because 107 ÷ 1.07 = 100.00, which means $7.00 of it was tax.
- Removing tax with a fractional rate. A $21.79 total at an 8.875% rate works out to a $20.01 pre-tax price and $1.78 of tax.
- Combining rates. If your state charges 6%, your county adds 1.5%, and your city adds 0.75%, the combined rate the calculator should use is 8.25%.
How Combined Rates Work
The rate printed on your receipt is almost always a combined rate. State sales tax is only the first layer; counties, cities, and special districts (for transit, stadiums, or other local purposes) can each add their own percentage on top. The seller adds all the applicable layers together and charges that single combined rate. Because the local add-ons stack, the combined rate in a large city can climb toward 9%. New York City, for example, charges a combined 8.875% made up of a 4% state rate, a 4.5% city rate, and a 0.375% district surcharge. Whatever your own layers add up to, enter that combined number as the rate.
Backing Tax Out of a Total
To remove tax from a tax-included total you divide by one plus the rate — you do not subtract the rate from the total. The difference matters. Take a $51.42 total that already includes 8.25% tax. Subtracting looks tempting: 51.42 × 0.0825 = $4.24, and 51.42 − 4.24 = $47.18. But that is wrong, because the 8.25% should apply to the smaller pre-tax price, not to the larger tax-included total. Dividing does it correctly: 51.42 ÷ 1.0825 = $47.50, the true pre-tax price. Remove mode always divides, so you get the right answer without doing the algebra yourself.
Common Mistakes
A few mistakes come up again and again. The first is subtracting the rate instead of dividing when backing tax out of a total, which overstates the tax and understates the original price. The second is using the state base rate when local add-ons apply — the combined rate on the receipt is usually higher, so a state-only rate underestimates the tax. The third is assuming everything is taxable. Many states exempt or reduce tax on certain categories, such as groceries or medicine, and what counts as taxable varies from state to state, so treat this calculator's result as an estimate for a standard taxable purchase.
States Without a Statewide Sales Tax
Five states have no statewide sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon. In four of them a typical retail purchase carries no sales tax at all. Alaska is the exception worth knowing: it has no state-level sales tax, but it lets local governments levy their own, so depending on the borough or city you may still pay a local sales tax at checkout. Everywhere else, expect a combined state-and-local rate.
A Note on Scope
One honest caveat: sales-tax rates and the rules about what is taxable change over time and vary widely by jurisdiction. The combined rate two towns apart can differ, and exemptions get added and removed. This calculator does the arithmetic once you supply a rate — it does not look up the current rate for your location, and it is a general estimate, not tax advice. For the rate that actually applies to your purchase, check your state's Department of Revenue.