Add sales tax to a purchase, reverse tax from a tax-inclusive total, or calculate the tax rate from before-tax and after-tax prices.
Calculator
Sales Tax Results
Review the before-tax amount, sales tax, and final total.
Purchase Breakdown
Calculation Details
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Sales tax calculator
Choose Add tax to calculate sales tax and the checkout total from a before-tax price. Choose Reverse tax when you know the tax-inclusive total and rate. Choose Find the sales tax rate when both the before-tax and after-tax prices are known.
sales tax = taxable amount x sales tax rate / 100
after-tax total = before-tax total + sales tax
Add sales tax example
A $100 taxable purchase at an 8.25% combined rate produces $8.25 of sales tax and a $108.25 total. If a discount applies, this calculator reduces the merchandise price before calculating tax.
Reverse sales tax
To remove sales tax from a tax-inclusive total, divide the total by one plus the rate as a decimal. For example, $108.25 divided by 1.0825 gives a $100 before-tax price and $8.25 tax.
before-tax price = tax-inclusive total / (1 + tax rate / 100)
Find the sales tax rate
Subtract the before-tax price from the after-tax price to find the tax amount, then divide by the before-tax price. A price that rises from $100 to $108.25 has an 8.25% implied sales tax rate.
tax rate = (after-tax price - before-tax price) / before-tax price x 100
Discounts, quantity, and shipping
In Add tax mode, the discount is applied to each item's price before multiplying by quantity. Shipping is added separately. Turn on Tax shipping only when shipping or handling is taxable for the actual transaction. For a broader promotion comparison, use the discount calculator.
Use the correct combined rate
Sales tax rules and rates can differ by state, county, city, product, and transaction. USAGov notes that states and municipalities can charge different percentages on different goods or no tax on some items. Use the combined rate from the relevant state or local tax authority rather than a statewide rate alone.
The IRS sales-tax deduction guidance also explains that local tax bases and rates can vary within a state. This calculator estimates transaction tax; it does not determine whether an item, buyer, seller, or shipping charge is taxable.
Total purchase cost
The FTC online-shopping guide recommends comparing the total cost, including shipping, handling, taxes, and other fees. Review the seller's checkout total before paying.
Frequently asked questions
How do I add 7% sales tax?
Multiply the taxable price by 0.07, then add that tax to the original price. A $50 purchase has $3.50 tax and a $53.50 total.
How do I remove tax from a total?
Divide the tax-inclusive total by one plus the rate as a decimal. Do not simply subtract the rate from the total.
Does sales tax apply before or after a discount?
This calculator applies tax after the entered discount. Actual treatment can vary with the jurisdiction and promotion.