Sales Tax Calculator
Free sales tax calculator. Calculate the total out-the-door price for any item, or back into the pre-tax price from a total — works for any state or local rate.
Quick answer
Total = pre-tax price × (1 + tax rate). To back into the pre-tax price from a total, divide the total by (1 + tax rate). U.S. combined state + local rates range from 0% (Oregon, Delaware, Montana, NH, Alaska) to 9.55% (Louisiana average).
Sales Tax Calculator
Total cost
How it works
Sales tax = price × (rate / 100). Total = price + tax. The calculator displays both the tax amount and the final out-the-door price you'll actually pay at the register.
When to use it
Estimating an out-of-state purchase, double-checking a receipt, budgeting a big-ticket item like furniture or electronics where the sales tax can be hundreds of dollars.
Common mistakes
Forgetting that local taxes stack on top of state taxes — most US cities add 1-3% on top of the state rate. The combined "all-in" rate is what you should enter here.
How the sales tax calculator works
The math is straightforward: a sales tax rate of r percent on a pre-tax price of P
gives a total of T = P × (1 + r/100). The calculator works in both directions:
enter pre-tax + rate to get the out-the-door price, or enter the total + rate to back into
the pre-tax amount. The reverse formula is P = T ÷ (1 + r/100) — useful when
you want to know how much of your receipt is the actual product cost vs. tax.
U.S. sales tax is a combined rate: the state rate plus any city, county, or special district rates. State rates range from 0% (Oregon, Delaware, Montana, New Hampshire, Alaska — though AK has many local taxes) to 7.25% (California). Local add-ons can push the combined rate past 10% in places like Chicago, IL (10.25%), Long Beach, CA (10.25%), and Birmingham, AL (10%). The Tax Foundation publishes a current map every January.
When to use it
Use this calculator when comparing prices across jurisdictions (a $1,000 laptop with no tax in Oregon vs. $1,102.50 in California vs. $1,100 in Chicago), when budgeting for a large purchase to know the real out-the-door cost, or when reconciling a business expense report and you need to back out the tax portion.
It is also the right tool when checking a vendor's invoice. Some vendors (especially online) apply tax to shipping, handling, or installation fees that are not always taxable in your jurisdiction. If your invoice tax doesn't match what this calculator predicts on the pre-tax subtotal, you have a discrepancy worth investigating.
Common mistakes
- Using the state rate only. The state rate is just the floor. Most ZIP codes have a higher combined rate after city/county/transit/special district add-ons. The South Dakota state rate is 4.2%, but combined rates in Sioux Falls hit 6.2%.
- Forgetting tax-exempt categories. Many states exempt groceries, prescription drugs, and clothing under a threshold. Some exempt feminine hygiene products. Don't apply your full combined rate to a grocery receipt and expect the math to match.
- Confusing tax rate with effective rate. If a $100 receipt shows $107.50 total and $7.50 tax, the rate is 7.5% (7.5/100), not 7% (7.5/107.50). Always divide tax by the pre-tax price, not the total.
- Forgetting that tax is rounded per item, not on the total. Some POS systems calculate tax line-by-line and round each, then sum. That can produce a total that is a penny or two off the rate × subtotal calculation.
- Assuming your home rate applies everywhere. Sales tax is generally based on the destination (where the goods are delivered), not your billing address. Online orders are taxed at the buyer's local rate, not the seller's.
Frequently asked questions
How do I calculate sales tax on a price?
Multiply the pre-tax price by (1 + the tax rate as a decimal). For a $50 item at a 7.5% rate: $50 × 1.075 = $53.75 total. The tax portion is $50 × 0.075 = $3.75.
How do I find the pre-tax price from a total?
Divide the total by (1 + the tax rate as a decimal). If the total is $107.50 at 7.5%, the pre-tax price is $107.50 ÷ 1.075 = $100. The tax was $7.50.
Which states have no sales tax?
Five states have no statewide sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon. Note that Alaska allows local jurisdictions to charge sales tax, so 'no state sales tax' does not always mean 'no sales tax at the register.'
Is sales tax based on where I live or where I shop?
For in-person purchases, the rate of the store's location applies. For online and mail-order purchases, the rate of the destination address applies — this is what's called destination-based sourcing, and it is the rule in most states post-Wayfair.
Why does my receipt show a different tax amount than the rate would suggest?
Three common causes: (1) some items on the receipt are tax-exempt (groceries, prescriptions, clothing under a threshold), (2) the POS rounded tax line-by-line then summed (small penny differences), or (3) shipping/handling/installation lines were taxed differently than the merchandise.