Sales Tax Calculator
Add sales tax to a price, or take it out of a total that already includes it, at any tax rate.
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Whether you are pricing a purchase, checking a receipt or filling in an expense report, you often need to know how much of a price is tax. This calculator works in both directions: it adds tax to a pre-tax price, or pulls the tax out of a total that already includes it.
How to use the sales tax calculator
- Choose what you know: the price before tax or the price including tax.
- Enter the amount.
- Enter the sales tax rate as a percentage, for example 8.25.
The calculator shows the total with tax, the tax itself and the price before tax.
Sales tax formulas
Adding tax to a price:
Tax = Price × Rate ÷ 100
Total = Price + TaxRemoving tax from a total that already includes it:
Price before tax = Total ÷ (1 + Rate ÷ 100)
Tax = Total − Price before taxWorked example: adding tax
You buy a $250 office chair where the combined sales tax rate is 8.25%.
- Tax = 250 × 8.25 ÷ 100 = $20.63 (20.625 rounded)
- Total = 250 + 20.63 = $270.63
Worked example: removing tax
A receipt shows a total of $108.25 at 8.25% tax, and you need the pre-tax price for an expense claim.
- Price before tax = 108.25 ÷ 1.0825 = $100.00
- Tax = 108.25 − 100 = $8.25
Why you cannot just subtract the percentage
A common mistake is to take 8.25% of the total and subtract it. On $108.25 that gives 108.25 − 8.93 = $99.32, which is 68 cents too low. The tax was calculated on the pre-tax price, not the total, so you have to divide to undo it. The gap gets bigger as the rate rises: with 20% VAT on a £120 total, subtracting 20% gives £96, but the real pre-tax price is £100.
How sales tax works in the US
There is no national sales tax in the United States. Each state sets its own rate, and counties, cities and special districts can add their own on top. As a result:
- A handful of states have no statewide sales tax at all.
- Combined rates in some cities go above 10%.
- Some items, such as groceries or prescription drugs, are exempt or taxed at a lower rate in many states.
Online purchases are generally taxed at the rate for the delivery address, so the same item can cost a different amount depending on where it is shipped.
Tips and pitfalls
- Use the combined rate. The state rate alone usually understates the tax you pay.
- Round once, at the end. Stores round the tax on the total, not on each item, so adding up per-item tax can be a cent or two out.
- Discounts usually come first. When a store discounts an item, tax is normally charged on the discounted price. Use our discount calculator first, then add tax.
- Keep receipts for business purchases. Depending on your situation, sales tax on business purchases may be deductible or recoverable.
Frequently asked questions
How do I calculate sales tax?
Multiply the price by the tax rate and divide by 100. At 8.25%, a $250 purchase has 250 × 8.25 ÷ 100 = $20.63 of tax, for a total of $270.63.
How do I remove sales tax from a total?
Divide the total by 1 plus the rate as a decimal. If you paid $108.25 at 8.25%, the price before tax was 108.25 ÷ 1.0825 = $100. Subtracting 8.25% of the total would give the wrong answer.
What sales tax rate should I use?
Use the combined rate for where the sale takes place. In the US this is usually the state rate plus any county and city rates, and it can differ between neighbouring towns. Your receipt or your state revenue department's website shows the exact rate.
Can I use this as a VAT or GST calculator?
Yes. VAT and GST work the same way mathematically. Enter the VAT or GST rate, for example 20%, and choose whether your amount includes it or not.