Sales Tax Calculator

A sales tax calculator multiplies the price by the tax rate written as a decimal, then adds the result. At a combined rate of 8.25%, a $49.99 item has $49.99 × 0.0825 = $4.124175 in tax, which rounds to $4.12, for a total of $54.11. To remove tax from a total, divide by 1.0825: $54.11 ÷ 1.0825 rounds to $49.99.

How to use the sales tax calculator

1. Pick what you want to find: Add tax to a price, Remove tax from a total, Find the rate from a receipt, or total a Shopping list.
2. Enter the rate. Type one combined rate, or switch to State + local layers and enter the state, county, city and special district rates separately. Leave a layer blank if it does not apply.
3. For a shopping list, enter each item’s price and quantity, and untick Taxable for items your state does not tax.
4. Read the answer, then open Show steps to see every multiplication and the rounding to the cent.

Sales tax formulas

Write the rate r as a decimal by dividing the percent by 100 (8.25% becomes 0.0825). Let P be the price before tax and T the total paid.

• Sales tax = P × r, rounded to the nearest cent.
• Total = P + tax, which is the same as P × (1 + r).
• Price before tax = T ÷ (1 + r).
• Tax rate = (T − P) ÷ P × 100.

All four come from one idea: tax is a percent of the price. For more practice with percents of a number, see the percentage calculator.

How combined sales tax rates work

In the United States, sales tax is usually set by more than one government. A state rate can be joined by a county rate, a city rate and one or more special district rates (for transit or other local purposes). The rate you pay is the sum of every layer that applies at the place of sale.

For example, with made-up rates of 6% state, 1% county, 1% city and 0.25% special district, the combined rate is 6 + 1 + 1 + 0.25 = 8.25%. The tax is then worked out once on the combined rate, not layer by layer.

Because local rates change and boundaries do not follow ZIP codes neatly, this page does not list state or local rates. Look up the rate for the exact address on your state’s tax agency website. The Federation of Tax Administrators keeps a directory of every state’s tax agency (see Sources).

Worked examples

Example 1: add tax to a price

A $49.99 item at 8.25%: 8.25 ÷ 100 = 0.0825, and $49.99 × 0.0825 = $4.124175. The third decimal place is 4, so the tax rounds down to $4.12. Total: $49.99 + $4.12 = $54.11.

Example 2: remove tax from a total

You paid $1,000.00 including 8.875% tax. Divide by 1.08875: $1,000.00 ÷ 1.08875 ≈ $918.48. The tax was $1,000.00 − $918.48 = $81.52. Check: $918.48 × 0.08875 = $81.5151, which rounds to $81.52, and $918.48 + $81.52 = $1,000.00.

Example 3: find the rate from a receipt

A $20.00 purchase came to $21.33. The tax is $1.33, and $1.33 ÷ $20.00 = 0.0665, or 6.65%. Because the receipt tax was rounded, any rate from 6.625% to 6.6749% gives $1.33. The roundest one, 6.625%, is the rate used in the New Jersey Division of Taxation’s own $20 example.

Removing sales tax: the reverse-percent mistake

The most common error is to take the tax rate off the total. With a $100.00 total at 8.25%, subtracting 8.25% of $100.00 gives $91.75. But the 8.25% was charged on the price, not on the total, so the right answer is $100.00 ÷ 1.0825 ≈ $92.38. The shortcut undercounts by $0.63, and the gap grows with the rate and the amount.

The same trap appears with discounts: a 20% discount followed by 20% tax does not bring you back to the starting price. The discount, tax and tip calculator handles all three in order.

Rounding sales tax to the cent

Sales tax is usually worked out to three decimal places and then rounded: half a cent or more rounds up to the next cent, and less than half a cent is dropped. The New Jersey Division of Taxation gives this example: $20 × 0.06625 = $1.325, which rounds up to $1.33. Minnesota’s rule, in Revenue Notice 05-08, is the same, and it applies the rounding to the combined state and local tax.

Some states let sellers use a published tax bracket table instead of multiplying. If a receipt is off by a cent, check your state’s rule.

Taxable and non-taxable items on one receipt

Many receipts mix taxed and untaxed goods. Add the taxable items, multiply that subtotal by the rate, then add the untaxed items with no tax. Which goods are taxed (groceries, clothing, medicine) depends on your state.

Sellers may also round per item or once per invoice. Minnesota, for one, lets the seller choose. With the calculator’s example list, rounding once gives $4.99 in tax and rounding each item gives $4.98. Use the Round the tax menu to compare.

Common sales tax mistakes

• Subtracting the rate from a total. Divide by 1 + r instead.
• Using only the state rate. Add every county, city and district layer.
• Forgetting to move the decimal. 8.25% is 0.0825, not 0.825.
• Rounding each layer separately. Round the combined tax once.
• Taxing exempt items. Leave them out of the taxable subtotal.

Can you deduct sales tax?

If you itemize deductions on Schedule A of Form 1040, the IRS lets you choose to deduct state and local general sales taxes instead of state and local income taxes, by checking box 5a. You can use your actual receipts or the IRS optional sales tax tables, and the IRS Sales Tax Deduction Calculator estimates the table amount. The deduction falls under a combined cap on state and local taxes, so check IRS Topic 503 for the limit that applies to your tax year.

Results on this page are estimates for checking arithmetic. They are not tax or legal advice, and sellers must follow their own state’s rules.

Sources

Checked November 2026.

• Minnesota Department of Revenue, Revenue Notice 05-08: rounding, per item or per invoice
• New Jersey Division of Taxation: calculating the sales tax
• IRS Topic No. 503, Deductible taxes
• IRS Sales Tax Deduction Calculator
• Federation of Tax Administrators: state tax agency directory

Sales tax practice quiz: 10 questions

Test yourself with 10 multiple-choice questions. Choose an answer and press Submit to see if you are right and why. Your score appears at the end.

Frequently asked questions

How do you calculate sales tax?

Divide the rate by 100 and multiply by the price, then round to the cent. At 7%, a $35.00 item has $35.00 × 0.07 = $2.45 in tax, so the total is $37.45.

How do I calculate sales tax backwards from a total?

Divide the total by 1 plus the rate as a decimal. A $107.00 total at 7% means $107.00 ÷ 1.07 = $100.00 before tax, so the tax was $7.00. Do not subtract 7% of $107.00; that gives $99.51.

How do I find the sales tax rate from a receipt?

Subtract the pre-tax subtotal from the total to get the tax, divide by the subtotal and multiply by 100. On an $80.00 purchase with a total of $86.60, the tax is $6.60 and $6.60 ÷ $80.00 = 8.25%.

What is a combined sales tax rate?

It is the state rate plus every local rate that applies at the place of sale: county, city and special districts. Add the layers, then apply the total once.

Why is my receipt one cent different from my calculation?

Usually because of rounding. The seller may round per item rather than once per receipt, or use a bracket table. The shopping list mode shows both rounding methods side by side.

Related calculators

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• Discount, tax and tip calculator
• Percent change calculator
• Rounding calculator
• Unit rate calculator (compare prices per unit)
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