Sales Tax Calculator
Add sales tax to a price, or find the tax hidden inside a total.
Formula
About this calculator
Sales tax works in two directions and this calculator does both. Most of the time you want to add tax: take a shelf price, apply your local rate, and see the final amount you'll pay at checkout. But sometimes you have a tax-inclusive total — a receipt, an invoice, an all-in price — and need to pull the tax back out to find the true pre-tax cost.
The reverse calculation trips people up. You cannot just take the same percentage off the total, because the tax was added to the smaller net figure, not the larger total. The correct method divides the total by one plus the rate. For example, at an 8% rate a $108 total is $108 ÷ 1.08 = $100 net, so the tax is $8 — not the $8.64 you'd get by taking 8% off $108.
US sales tax rates vary widely by state and even by city, from 0% in states like Oregon and Delaware to over 10% in some local jurisdictions, so always enter your own combined rate. Sales tax is separate from income tax — to see what you keep from your paycheck, use the take-home-pay calculator.
Frequently asked questions
How do I calculate sales tax on a price?
Multiply the pre-tax price by the tax rate as a decimal, then add it back. A $100 item at 7.25% is $100 × 0.0725 = $7.25 tax, for a $107.25 total.
How do I find the tax inside a total price?
Divide the total by one plus the rate to get the net, then subtract. A $107.25 total at 7.25% is $107.25 ÷ 1.0725 = $100 net, so $7.25 was tax.
Why can't I just subtract the percentage from the total?
Because the tax was added to the smaller net amount, not the total. Subtracting the rate from the total over-estimates the tax. Always divide by one plus the rate instead.