Add sales tax to a price, or enter a receipt total and work backward to the pre-tax price and the exact tax amount. Works with any tax rate you enter.
How the sales tax calculator works
Forward is easy: tax is a percentage of the pre-tax price, so the total is price × (1 + rate). The genuinely useful trick is the reverse direction — you're staring at a receipt total, an expense report, or a "tax included" price and need the pre-tax amount. Since the total already contains the tax, you divide by (1 + rate) rather than subtracting a percentage. This calculator does both; flip the mode toggle to go backward.
The formulas
Total = Price × (1 + rate ÷ 100)
Pre-tax price = Total ÷ (1 + rate ÷ 100)
Rate is the combined sales tax percentage. The tax amount is always the difference between the total and the pre-tax price.
Worked example
Adding tax: a $60 item at 7.5% → tax = 60 × 0.075 = $4.50, total = $64.50.
Reverse: a receipt total of $100.00 at 6% → pre-tax price = 100 ÷ 1.06 = $94.34, so the tax was $5.66.
The reverse-tax trap (and a note on US rates)
The classic mistake is taking the tax rate straight off the total: 6% of $100 is $6.00, but the actual tax in the example above is $5.66. Why? The 6% was charged on $94.34, not on $100 — subtracting 6% of the total taxes the tax. The gap grows with the rate, so at 10% you'd be off by nearly 1% of the whole purchase.
Also worth knowing: there is no single "US sales tax." Rates are set by states, counties, cities, and special districts, and the combined rate can differ across a street. This calculator deliberately takes whatever rate you give it — grab the exact combined rate from a receipt or your state revenue site for a precise answer.
Frequently asked questions
How do I calculate sales tax on a price?
Multiply the pre-tax price by the tax rate as a decimal. At 7.5%, a $60 item carries $60 × 0.075 = $4.50 of tax, for a total of $64.50. Equivalently, multiply the price by (1 + rate) in one step: $60 × 1.075 = $64.50.
How do I find the price before tax from a total?
Divide the total by (1 + rate). If a receipt shows $100.00 in a 6% area, the pre-tax price is $100 ÷ 1.06 = $94.34, and the tax was $5.66. Switch this calculator to reverse mode and it does exactly that.
Why can't I just subtract the tax rate from the total?
Because the tax was charged on the pre-tax price, not on the total. Taking 6% of a $100 total gives $6.00, but the real tax was $5.66 — you'd be taxing the tax. Dividing by (1 + rate) is the correct reverse calculation.
What sales tax rate should I use?
Use your combined rate: state rate plus any county, city, and special-district rates that apply where the sale happens. In the US these vary widely — combined rates run from 0% to over 10% depending on location. Check your receipt or your state's revenue department site, then enter that number here.
Which US states have no sales tax?
Delaware, Montana, New Hampshire, and Oregon have no state or local sales tax. Alaska has no state sales tax, but some Alaskan municipalities charge their own local rates. Everywhere else, expect a state rate plus possible local add-ons.