Formula
Tax = price × rateTotal = price × (1 + rate)Price before tax = total ÷ (1 + rate) How it works
Sales tax in the United States is set by states, counties and cities, and the combined rate where you shop is what applies. State rates range from 0% to 7.25%, and local add-ons push combined rates above 9% in some places. Five states — Alaska, Delaware, Montana, New Hampshire and Oregon — have no statewide sales tax, though Alaska allows local ones.
To back the tax out of a receipt total, divide by one plus the rate rather than subtracting the rate from the total. Subtracting 8% from $108 gives $99.36, but the real pre-tax price is $108 ÷ 1.08 = $100.
Many states exempt or reduce tax on groceries, prescription drugs and clothing, so the right rate depends on what you are buying. The same calculation works for VAT or GST in other countries.
Frequently asked questions
How do I find my local sales tax rate?
Your state revenue department publishes rates by address or ZIP code. Receipts from local stores also show the combined rate.
Is sales tax charged on online purchases?
Usually yes. Since 2018 states can require online sellers to collect sales tax based on where the item is shipped, and all states with a sales tax now do.
Is sales tax deductible?
If you itemize on your federal return you can deduct either state income tax or sales tax, within the overall cap on state and local tax deductions.