Finance & Money
Sales Tax Calculator
Use the sales tax calculator to estimate checkout totals or reverse-check a receipt before you buy.
Total after tax
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- Sales tax
- —
- Discount
- —
- Taxable amount
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Student quick launch
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Study path
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What this sales tax calculator solves
It answers the checkout question: what will this actually cost? Enter the sticker price, your local sales tax rate, and any pre-tax discount, and it returns the discount amount, the taxable amount, the tax, and the final total — the same arithmetic the register runs.
The formula
The discount is applied first, shrinking the taxable amount; tax is then charged on what you actually pay, not the original sticker price. That ordering matters — taxing before discounting would overstate the total.
$120 jacket, 20% off, 8.5% tax
Discount: 120 x 0.20 = $24. Taxable amount: 120 - 24 = $96. Tax: 96 x 0.085 = $8.16. Total: 96 + 8.16 = $104.16. Note the tax was charged on $96, not $120.
Why rates differ so much
In the U.S., sales tax is set locally, not federally. The rate you pay is usually a stack: a state rate plus county, city, and special-district add-ons. That is why the combined rate can change when you cross a city line, and why a handful of states charge no general sales tax at all. Rates also change over time, so check your current local combined rate rather than assuming last year's number.
- Use the combined state + county + city rate for your location, not just the state rate.
- Some categories (groceries, prescription drugs, clothing) are taxed at reduced rates or exempt in some places.
- Store coupons usually reduce the taxable amount, but manufacturer coupons and rebates can be treated differently.
- Tips, shipping, and bottle deposits may sit outside the taxable amount depending on local rules.
How to use it
- Enter the pre-tax price.
- Enter the local tax rate.
- Add any pre-tax discount if needed.
How to read the answer
The total is the estimated checkout amount before tips, shipping, or special fees.
Common mistakes and edge cases
- Sales tax rules vary by location and item type.
- Some discounts are applied after tax, depending on store rules.
- Use the local combined tax rate for city, county, and state tax.
Worked examples
Standard purchase
Total after tax
$91.16
Discounted purchase
Total after tax
$104.16
Frequently asked questions
Is sales tax calculated before or after a discount?+
Usually after the discount, but rules can vary. This calculator assumes the discount lowers the taxable amount.
Can this reverse sales tax?+
This page estimates forward from pre-tax price. A reverse-sales-tax mode can be added later.
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Last updated: May 8, 2026