Sales Tax Calculator
Add sales tax to a price, or work backwards to back out the tax from a total you already paid. Enter any combined tax rate and instantly see the tax amount and the pre-tax price.
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Pick a mode, type a dollar amount and your tax rate. The results update as you type.
How sales tax works
Sales tax is a percentage added to the price of taxable goods and services at the point of sale. In the United States it isn't a single national rate — most states set a statewide base rate, and then counties, cities and special districts can stack their own local rates on top. The number on your receipt is the combined rate: state + county + city + any district taxes where the sale happens.
Because of that stacking, the rate varies by location. Two shops a few miles apart can charge different combined rates, and an online order is usually taxed based on the delivery address. A few states have no statewide sales tax at all, while others run double-digit combined rates once local add-ons are included.
Not everything is taxed. Many states exempt categories like groceries, prescription drugs or clothing, or tax them at a reduced rate. That's why this calculator asks you for the rate directly — you plug in whatever combined rate applies, and it handles the arithmetic.
The formula & how we calculate it
Adding sales tax is straightforward: convert the rate to a decimal, multiply it by the price to get the tax, then add the tax to the price.
price = the amount before tax
rate = the combined sales tax rate, as a percent
Worked example — $100 at 7.25%:
- Convert the rate: 7.25% ÷ 100 = 0.0725.
- Tax = $100 × 0.0725 = $7.25.
- Total = $100 + $7.25 = $107.25.
Reversing it — backing out the tax. If you only know the total you paid, you can't just subtract the rate. Instead, divide the total by one plus the rate as a decimal:
Worked example — $107.25 total at 7.25%:
- 1 + 0.0725 = 1.0725.
- Pre-tax price = $107.25 ÷ 1.0725 = $100.00.
- Tax = $107.25 − $100.00 = $7.25.
This is why the "Remove" mode exists — subtracting 7.25% of the total would wrongly give $99.47, not $100.00.
What affects the sales tax you pay
- Location. The combined rate is built from state, county, city and special-district taxes. In-store it's the store's location; for shipped orders it's usually the delivery address.
- Type of item. Many states exempt or reduce tax on essentials like groceries, prescription medicine and sometimes clothing.
- Online vs. in-store (nexus). Since 2018, online sellers generally must collect sales tax in states where they have economic "nexus," so most online orders are now taxed at your delivery address's rate.
- Shipping & handling. Whether delivery charges are taxable depends on the state and how the charge is listed.
- Exemptions & holidays. Resale certificates, nonprofit exemptions and temporary "sales tax holidays" can change or remove the tax on a purchase.
Glossary
- Sales tax
- A percentage charged on the sale of taxable goods and services, collected by the seller and passed to the government.
- Tax rate
- The percentage applied to the price — the combined sum of state, county, city and special-district rates at the point of sale.
- Pre-tax price (net)
- The price of the item before sales tax is added — the amount the tax is calculated on.
- Gross (total with tax)
- The final amount you pay, including the sales tax. Backing out the tax converts gross to net.
- Use tax
- A counterpart to sales tax owed by the buyer when sales tax wasn't collected at purchase — for example some out-of-state purchases.
- Exemption
- A rule that removes or reduces sales tax for certain items (like groceries) or buyers (like resellers or nonprofits).
Frequently asked questions
How do I calculate sales tax?
Multiply the price before tax by the sales tax rate as a decimal. For 7.25%, multiply by 0.0725 — on a $100 purchase the tax is 100 × 0.0725 = $7.25, and the total is $107.25. Your combined rate is the state rate plus any county, city and district rates where you buy.
How do I add sales tax to a price?
Multiply the pre-tax price by the rate as a decimal to get the tax, then add it: Tax = price × (rate ÷ 100) and Total = price + tax. For $100 at 7.25%, tax is $7.25 and total is $107.25. The Add mode above does this automatically.
How do I remove or back out sales tax from a total?
Divide the total by one plus the rate as a decimal: pre-tax = total ÷ (1 + rate ÷ 100); the tax is the difference. For a $107.25 total at 7.25%, the pre-tax price is $100.00 and the tax was $7.25. Don't simply subtract the rate. Use Remove mode above.
What is 7.25% sales tax on $100?
It's $7.25, for a total of $107.25 (100 × 0.0725 = 7.25). 7.25% is California's statewide base rate; local add-ons often make the combined rate higher.
Why does sales tax vary by location?
States set a base rate, then counties, cities and districts add local rates on top. The combined rate is based on where you take possession of the item, so two nearby stores — or an online order to a different ZIP — can differ. A few states have no statewide sales tax.
Is shipping taxable?
It depends on the state and how the charge is invoiced. Some states tax shipping when the item is taxable; others exempt separately stated shipping. Check your state's rules or your receipt.