Sales Tax Calculator
Figure out sales tax on any purchase in seconds. Enter a pre-tax amount and your sales tax rate to instantly see the tax amount and the total with tax — or switch to reverse mode to back the sales tax out of a tax-inclusive total.
ToolsSoup's Sales Tax Calculator works out how much sales tax you owe on a purchase and what the final price comes to. Type a pre-tax amount and your sales tax rate and you immediately see the sales tax in dollars and the total with tax. Use "Add tax" to mark a price up to its checkout total, or switch to "Back out tax" to pull the tax out of a tax-inclusive total when you only know the amount you paid. It works with any combined state and local rate — California's 7.25% base, Chicago's 10.25%, a flat 6% or 8%, or your own custom percentage. Everything runs in your browser: no uploads, no sign-up, and your numbers never leave your device.
What is sales tax?
Sales tax is a percentage that most U.S. states and local governments add to the price of taxable goods and services at the point of sale. The store collects it from the shopper at checkout and remits it to the state. The rate you actually pay is usually a combined rate — a statewide rate plus county, city, and special-district add-ons — so two stores in the same state can charge different totals. Because the tax is a percentage of the pre-tax price, a $100 item at an 8% rate carries $8 of sales tax and rings up at $108 total.
How to calculate sales tax
Use "Add tax" mode when you have a pre-tax (ticket) price and want to know the checkout total:
- Choose "Add tax" mode.
- Enter the pre-tax amount — the price on the shelf or invoice.
- Enter your combined sales tax rate, for example 7.25.
- Read the sales tax and the total with tax below.
How to back out sales tax from a total
Use "Back out tax" mode when you only have the final amount you paid and need to split it into the pre-tax price and the tax — handy for expense reports and bookkeeping. The calculator divides the total by 1 plus the rate, so a $108 receipt at an 8% rate breaks down into a $100 pre-tax amount and $8 of sales tax.
- Choose "Back out tax" mode.
- Enter the total with tax — the amount you actually paid.
- Enter the sales tax rate that was charged.
- Read the pre-tax amount and the sales tax that was included below.
What is the sales tax formula?
To add sales tax: tax = pre-tax amount × rate ÷ 100, and total = pre-tax amount + tax. For a $100 purchase at 7.25%, the tax is $7.25 and the total is $107.25. To back tax out of a total you reverse it: pre-tax = total ÷ (1 + rate ÷ 100), then tax = total − pre-tax. For a $107.25 total at 7.25%, pre-tax = 107.25 ÷ 1.0725 = $100 and the tax is $7.25. A common mistake is taking the rate off the tax-inclusive total to find the tax, which overstates it — you have to divide, not multiply, when working backward.
Why use this sales tax calculator?
- Adds sales tax to a price and backs sales tax out of a total in one tool.
- Shows the pre-tax amount, the sales tax, and the total together so the breakdown is always clear.
- Works with any combined state and local rate — 7.25%, 8.25%, 10.25%, or your own custom percentage.
- Uses the correct reverse formula (divide by 1 + rate) so the tax pulled out of a total is accurate.
- Updates live as you type, runs entirely in your browser, and is 100% free with no ads or sign-up.
Frequently asked questions
How do I calculate sales tax on a purchase?
Multiply the pre-tax price by your sales tax rate to get the tax, then add it to the price for the total. At an 8% rate, a $100 purchase has $8 of sales tax and a $108 total. Choose "Add tax" above, enter the amount and rate, and the calculator does it instantly.
How much is sales tax on $100?
It depends on your combined rate. At 7.25% the sales tax is $7.25 and the total is $107.25; at 8% it's $8 and $108; at 10% it's $10 and $110. Enter 100 and your local rate in "Add tax" mode to see your exact numbers.
How do I figure out the sales tax from a total?
Divide the total you paid by 1 plus the rate as a decimal, then subtract to get the tax. At 8%, $108 ÷ 1.08 = $100 pre-tax, leaving $8 of sales tax. Switch to "Back out tax" above to do this automatically.
Which sales tax rate should I use?
Use the combined rate that applies where the sale happens — the statewide rate plus any county, city, and district taxes. Rates range from 0% in states with no sales tax to over 10% in some cities, so check your locality and enter that combined percentage.
Do all U.S. states charge sales tax?
No. Alaska, Delaware, Montana, New Hampshire, and Oregon have no statewide sales tax (though some localities in Alaska add a local tax). In those places you can enter 0, or just the local rate, and the total will equal the pre-tax amount.
What's the difference between sales tax and VAT?
Sales tax is charged once, at the final retail sale to the consumer, and is the U.S. model. VAT (value added tax), used in the EU, UK, and many other countries, is collected in stages along the supply chain. This tool calculates U.S.-style sales tax; for VAT use our VAT calculator instead.