Sales Tax CalculatorFree online financial calculator — instant results, no sign-up
Add or remove sales tax from a price.
Estimates only, based on the inputs and assumptions shown. This is not financial, investment, tax, or legal advice. Prices, rates and local rules may change; crypto scenarios do not predict returns. Confirm important decisions with a qualified professional.
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About the Sales Tax Calculator
This calculator computes the sales tax amount and the final total for a given purchase price and tax percentage. It also calculates the reverse: what the original pre-tax base price would be if the entered price already included sales tax. Shoppers, small business owners, and bookkeepers use it to verify receipts and accurately price goods.
- Price before tax
- The monetary cost of an item or service prior to sales tax, entered in dollars (typically $0.01 or greater).
- Tax rate
- The applicable combined state and local sales tax rate entered as a percentage (typically between 0% and 15%).
Formula and method
Tax = p × (rate / 100) Price after tax = p × (1 + rate / 100) If price included tax, pre-tax = p / (1 + rate / 100)
- pEntered base price in dollars
- rateSales tax rate expressed as a percentage
The calculator multiplies the input price by the percentage rate to find the tax amount, then adds it to the base price to get the total after tax. In parallel, it divides the input price by one plus the tax rate decimal to determine the pre-tax price in reverse scenarios. All monetary amounts are rounded to standard two-decimal currency formatting.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Price before tax100 $
- Tax rate8.25 %
Results
- Tax$8.25
- Price after tax$108.25
- If price included tax, pre-tax$92.38
How to use the Sales Tax Calculator
- 1Convert the tax rate percentage into a decimal by dividing it by 100.
- 2Multiply the pre-tax price by this decimal to determine the sales tax amount.
- 3Add the calculated sales tax to the original price to produce the final price after tax.
- 4Divide the initial price by one plus the tax decimal to find the pre-tax amount if the entered figure already included tax.
Reading your result
The 'Tax' output shows the exact dollar surcharge owed under the specified rate, while 'Price after tax' is the full out-of-pocket total. The 'If price included tax, pre-tax' row reveals how much of that total was the underlying merchandise cost if you entered a gross receipt total.
Limitations
The calculator assumes a single uniform tax rate applied to the entire amount, without accounting for tiered tax thresholds, variable line-item exemptions (such as unprepared food or prescription drugs), or compound local district surcharges.
Common questions
How do I calculate what portion of a receipt total was sales tax?+
Enter your receipt total into the 'Price before tax' field. The result labeled 'If price included tax, pre-tax' shows the original cost before tax; subtracting that amount from your total gives the exact tax paid.
Why can't I just subtract the tax rate percentage from a tax-inclusive total?+
Subtracting a percentage from a gross amount produces an incorrect number because the sales tax was originally calculated on the smaller pre-tax base, not the larger post-tax total. You must divide by (1 + tax rate) instead.
What rate should I enter if my purchase has both state and city tax?+
Combine the state, county, and local city tax percentages into a single combined percentage (for example, 6.25% state plus 2.0% local equals 8.25%) before entering it into the tax rate field.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.