Sales Tax Calculator
Sales tax on a $100 purchase at an 8% rate is $8.00, for a total of $108.00. Enter the amount and your tax rate, then choose whether to add tax to a price or remove tax from a total that already includes it. The calculator shows the pre-tax amount, the sales tax, and the final total. The calculation assumes one percentage applies to the entire entered amount. Actual tax can depend on the sale location, delivery address, product type, buyer status, tax holiday, marketplace rules, and whether shipping or fees are taxable. The calculator does not look up a jurisdiction or decide whether a transaction is taxable. Use the combined rate that applies to the specific sale and check the result against an official source when reporting or collecting tax.
Quick answer
Adding tax multiplies the price by the rate to find the tax, then adds it to the price.
What this tells you
- •Adding tax multiplies the price by the rate to find the tax, then adds it to the price.
- •Removing tax divides a tax-inclusive total by one plus the rate to find the pre-tax price.
- •The sales tax is the difference between the total and the pre-tax amount.
- •Removing tax is not the same as subtracting the stated percentage from the tax-inclusive total.
- •The rate must be the combined rate for the transaction, including applicable local components.
- •Fees and shipping are included only if you add them to the entered taxable amount.
How to Use
- 1Enter the dollar amount.
- 2Enter your local sales tax rate as a percentage.
- 3Choose Add tax to a price or Remove tax from a tax-inclusive total.
- 4Click Calculate to see the pre-tax amount, sales tax, and total.
- 5Confirm whether the item, shipping, service charge, or buyer qualifies for an exemption.
- 6For filing or invoicing, compare the result with the rules and rounding method required by the taxing authority.
How It Works
Formula
Add tax: Sales Tax = Amount x Rate / 100, Total = Amount + Sales Tax
Remove tax: Pre-Tax = Amount / (1 + Rate / 100), Sales Tax = Amount - Pre-TaxAdding tax treats the entered amount as the pre-tax price and applies the rate to it. Removing tax treats the entered amount as a total that already includes tax, so it divides by one plus the rate to recover the original price and reports the tax as the difference.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Add 8% tax to a $100 purchase
Sales tax is 100 x 8 / 100 = $8.00. The total is 100 + 8 = $108.00, and the pre-tax amount stays $100.00.
Remove 8% tax from a $108 total
Pre-tax price is 108 / 1.08 = $100.00. The sales tax is 108 - 100 = $8.00, and the total is the $108.00 you started with.
Add 7.25% tax to a $249.99 purchase
$249.99 x 0.0725 equals $18.124275, which displays as $18.12. Adding the unrounded tax before final display produces a $268.11 total.
Remove 6.5% tax from a $532.50 total
Dividing $532.50 by 1.065 gives $500.00. The difference between the entered total and the recovered price is $32.50.
A purchase with a 0% entered rate
At an entered rate of zero, the formula adds no tax. This may describe a zero-rate jurisdiction or an exempt transaction, but the calculator cannot determine why the rate is zero.
A laptop with a combined state and local rate
Dana buys a $1,849 laptop in a city where the state charges 6.25% and a local option tax adds 2%, so she enters the combined 8.25% rather than either piece alone. Sales tax is 1,849 x 8.25 / 100 = $152.54, and the total is $2,001.54. Entering only the 6.25% state rate would show $115.56 in tax, which is $36.98 less than the register will charge.
Sales Tax and Total at Common Combined Rates
Sales tax and out-the-door total on a $1,500 purchase and a $25,000 purchase at six combined state plus local rates, computed with the add-tax formula above.
| Combined rate | Purchase | Sales tax | Total |
|---|---|---|---|
| 4% | $1,500 | $60.00 | $1,560.00 |
| 4% | $25,000 | $1,000.00 | $26,000.00 |
| 6% | $1,500 | $90.00 | $1,590.00 |
| 6% | $25,000 | $1,500.00 | $26,500.00 |
| 7% | $1,500 | $105.00 | $1,605.00 |
| 7% | $25,000 | $1,750.00 | $26,750.00 |
| 8.25% | $1,500 | $123.75 | $1,623.75 |
| 8.25% | $25,000 | $2,062.50 | $27,062.50 |
| 9.5% | $1,500 | $142.50 | $1,642.50 |
| 9.5% | $25,000 | $2,375.00 | $27,375.00 |
| 10.25% | $1,500 | $153.75 | $1,653.75 |
| 10.25% | $25,000 | $2,562.50 | $27,562.50 |
Computed with the formula above: sales tax = amount x rate / 100, total = amount + tax, rounded to cents. The rates are examples of combined state plus local totals, not the rate for any specific place. Look up the combined rate for the delivery address and the transaction date before collecting or reporting tax.
Adding and extracting sales tax
Adding sales tax starts from a price before tax. You multiply the price by the rate to find the tax, then add it on. This is what happens at the register when a listed price gets tax applied at checkout.
Removing sales tax, sometimes called reverse sales tax, starts from a total that already includes tax. To find the original price, you divide the total by one plus the rate as a decimal. For an 8% rate, divide by 1.08. The tax is the difference between the total and that pre-tax price.
Use the remove mode when a receipt only shows the final amount and you need the pre-tax figure for an expense report or bookkeeping. Use the add mode when you know a list price and want to see the out-the-door cost.
Subtracting 8% from a tax-inclusive $108 total would give $99.36, not the original $100 price. The reason is that the $8 tax was 8% of the pre-tax price. It was only about 7.41% of the final total. Division by 1.08 reverses the original multiplication correctly.
Tax systems can round each line item, each jurisdiction component, or the invoice total. This calculator rounds its three displayed results to cents after applying one combined rate. A point-of-sale system may differ by a cent when it uses another permitted rounding sequence.
Where the rate comes from matters as much as the arithmetic. Five states have no statewide general sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon, although Alaska allows local governments to levy their own. Everywhere else the rate on a receipt is the state rate plus any local option taxes for the county, city, transit district, or special district, and that combined figure is what belongs in the Tax Rate field. Since the Supreme Court decided South Dakota v. Wayfair, Inc. in 2018, a state may require a remote seller with no physical presence there to collect its tax, so an online order is generally taxed at the rate for the delivery address rather than the seller's location.
Common mistakes
- Entering the rate as a decimal like 0.08 instead of a percentage like 8
- Adding tax when the amount already includes it, which double counts the tax
- Using a single state rate when the combined local rate is higher
- Forgetting that some items, such as groceries or clothing, may be tax exempt
- Subtracting the tax percentage directly from a tax-inclusive amount instead of dividing by one plus the rate
- Leaving taxable delivery charges or mandatory fees out of the taxable base when local rules include them
- Applying one rate to a mixed basket when individual products have different tax treatment
- Assuming an online seller uses the seller's location rather than the delivery destination or another sourcing rule
Limitations
This calculator applies one entered percentage to one positive amount and rounds the three displayed results to cents. It does not look up a rate, and rates change: legislatures amend statewide rates and local governments add or adjust option taxes, so confirm the combined rate for the transaction date and delivery address with the state revenue department. Since South Dakota v. Wayfair, Inc. (2018) a remote seller may have to collect at the buyer's location, and the tool cannot tell which jurisdiction applies. It does not decide nexus, product taxability, exemptions, resale status, tax holidays, shipping, fees, discounts, trade-ins, excise taxes, value-added tax, or use tax. It also does not reproduce jurisdiction rounding: member states of the Streamlined Sales and Use Tax Agreement, for example, carry the tax to the third decimal and round up when that digit is greater than four, on either an item or an invoice basis (SSUTA Section 324), so a register can differ from this result by a cent. A price quoted with tax already included must go through Remove mode, and the dollar sign is a display label that does not convert currency.
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