Sales Tax Calculator
Work sales tax in either direction: add tax to a sticker price to see the checkout total, or start from a receipt total and back out how much of it was tax.
Before tax
$100.00
Sales tax
$7.00
Total
$107.00
Combined state + local rates in the US range from 0% (Delaware, Montana, New Hampshire, Oregon) to over 10%; the national average is about 7.5%. Check your locality's combined rate — city and county taxes stack on the state rate.
The Two Directions of Sales Tax Math
Adding tax is simple multiplication. Backing it out is the one people get wrong: you divide by one-plus-the-rate rather than subtracting the percentage, because the tax was charged on the smaller pre-tax amount, not on the total.
Formulas
Adding tax: Total = Price × (1 + rate) $100 × 1.07 = $107.00 Backing tax out of a total: Price = Total ÷ (1 + rate) $107 ÷ 1.07 = $100.00 → tax was $7.00 (Common mistake: $107 − 7% = $99.51 ✗)
Frequently Asked Questions
How do I figure out the tax from a receipt total?
Divide the total by 1 plus the rate. A $107 total at 7% tax: $107 ÷ 1.07 = $100 pre-tax, so the tax was $7. Use the 'price includes tax' mode for this — subtracting 7% of the total is the common mistake and gives the wrong answer.
Which US states have no sales tax?
Delaware, Montana, New Hampshire, and Oregon have no state or local sales tax. Alaska has no state-level tax, but some Alaskan municipalities levy their own local sales taxes.
Why is the rate I'm charged higher than my state's rate?
City, county, and special-district taxes stack on top of the state rate. A state with a 6.25% base can have localities collecting over 8% combined. The rate at the register reflects the delivery or store location's total stack.
Do online orders charge sales tax?
Generally yes since the 2018 Wayfair decision — large retailers must collect tax based on your shipping address, at your local combined rate. Small sellers under a state's economic threshold may not, which is why occasional marketplace orders still arrive untaxed.