Finance calculators

Reverse Sales Tax Calculator

Updated Aug 15, 2026 By Jehan Wadia
Rate Formulas

Enter Your Purchase Details

Enter the total amount you paid, including sales tax.
Enter the sales tax rate percentage applied to your purchase.
Choosing a state will auto-fill the tax rate. You can still edit the rate manually.
Common Rates:

Your Reverse Sales Tax Results

Original Price (Before Tax)
$100.00
Tax Amount Paid
$8.25
Final Price (With Tax)
$108.25

Detailed Breakdown

Receipt-style breakdown of the pre-tax price, the sales tax, and the total paid.
Original Price:$100.00
Tax (8.25%):+$8.25
Total:$108.25

Step-by-Step Solution — How This Was Calculated

Shortcut: When the sales tax rate is 8.25%, divide the total price by 1.0825 to find the original pre-tax price.

Price Composition


Receipt Overcharge Checker

Enter the total you paid as shown on your receipt.
Enter the subtotal shown before tax on your receipt.
Enter the applicable sales tax rate for this purchase.
Tax You Were Charged$9.00
Tax You Should Have Paid$8.25
Difference$0.75
Effective Rate Charged9.00%

Introduction

A reverse sales tax calculator works backward from a total price. You type in the amount you paid and the tax rate. It shows you the original price before tax and how much of that money was tax.

This helps when a receipt only shows one number. It also helps when you need the pre-tax price for a business expense, an expense report, or a tax deduction. Sellers use it too, when a shelf price already includes tax and they need to split out the tax to report it.

The math is simple. Divide the total by 1 plus the tax rate. If you paid $108.25 with an 8.25% tax rate, divide $108.25 by 1.0825. The original price was $100.00, and the tax was $8.25. If you want to work the other direction and add tax to a price, use the Sales Tax Calculator instead.

This tool does that math for you. Pick your state to fill in the average rate, or tap a common rate button, or type your own. You get the pre-tax price, the tax amount, a receipt-style breakdown, and step-by-step work you can check. There is also a Receipt Overcharge Checker that compares the tax you were charged to the tax you should have paid, so you can spot a mistake before you leave the store.

How to use our Reverse Sales Tax Calculator

Enter the total price you paid and the sales tax rate. The calculator shows the original price before tax, the tax amount you paid, a step-by-step solution, and a chart of your price breakdown.

Final Price (With Tax): Type the full amount from your receipt, including sales tax. For example, enter 108.25.

Sales Tax Rate: Type the tax rate as a percent, like 8.25. You can find this on your receipt. If you only know the dollar amount of tax and the subtotal, the Tax Percentage Calculator can find the rate for you.

Select State / Jurisdiction (Optional): Pick your state to fill in the average tax rate for you. You can still change the rate by hand. For state-specific figures, see the State Tax Calculator, the Missouri Sales Tax Calculator, the NJ Sales Tax Calculator, or the NYC Sales Tax Calculator.

Common Rates: Tap a button like 7% or 8.875% to set that rate fast.

Calculate: Select this to see your pre-tax price, tax paid, and total. Use Reset Calculator to start over.

Total Amount Paid (Overcharge Checker): Type the total on your receipt to check if the store charged the right tax.

Pre-Tax Price on Receipt: Type the subtotal shown before tax was added.

Tax Rate (%): Type the tax rate that should apply to your purchase.

Check Receipt: Select this to compare the tax you were charged with the tax you should have paid. The result tells you if you were overcharged, undercharged, or charged correctly.

What Is Reverse Sales Tax?

Reverse sales tax means working backward. You start with the total price you paid, and you take the tax out of it. What is left is the original price of the item before tax. This is also called a "sales tax backwards" or "pre-tax price" calculation. The same idea applies to other tax systems too, which is why there are separate tools like the Reverse Tax Calculator, the Remove VAT Calculator, and the GST Calculator.

The Formula

To find the price before tax, divide the total by 1 plus the tax rate:

  • Original Price = Total Price ÷ (1 + Tax Rate)
  • Tax Paid = Total Price − Original Price

Example: You paid $108.25 and the tax rate is 8.25%. Turn 8.25% into 0.0825. Add 1 to get 1.0825. Then $108.25 ÷ 1.0825 = $100.00. The tax you paid was $8.25.

Why You Should Not Just Subtract the Percent

A common mistake is taking 8.25% off the total. That gives the wrong answer. Tax is added on top of the smaller pre-tax price, not the bigger total. Taking a percent off the total removes too much money. Always divide instead. If you want to see how big that gap is, run both numbers through the Percentage Calculator or the Percent Difference Calculator.

When People Need This

  • Business expenses: Sales tax is often listed apart from the item cost in your books, which matters when you figure margin or markup on what you sell.
  • Tax deductions: Some people deduct state and local sales tax on their federal return, which lowers taxable income and can change your refund.
  • Faded or missing receipts: If the receipt only shows one number, you can split it back out.
  • Price setting: Sellers who want a round total price, like $20.00 out the door, need to know the pre-tax amount. Online sellers should also check the eBay Fee Calculator, Etsy Fee Calculator, or PayPal Fee Calculator.
  • Refunds and returns: You get the tax back too, so you need to know how much of the total was tax.
  • Tax-free shopping: Travelers and resellers claiming a refund must show the tax portion. Imported goods may also carry a customs duty on top.

About U.S. Sales Tax Rates

There is no national sales tax in the United States. Each state sets its own rate, and cities and counties can add more on top. That is why a rate can look odd, like 8.875% in New York City or 9.55% in Tennessee. Five states — Alaska, Delaware, Montana, New Hampshire, and Oregon — have no statewide sales tax, though some Alaska towns still charge a local tax. Sales tax is separate from income tax, so for wage withholding see the Income Tax Calculator or the Paycheck Calculator.

Rates also change by what you buy. Many states tax groceries, medicine, or clothing at a lower rate or not at all. If your receipt has both taxed and untaxed items, run the numbers only on the taxed part. Big-ticket buys such as a car often carry their own rules — the Out The Door Price Calculator and the Road Tax Calculator handle those.

Checking a Receipt for Overcharges

Stores make errors. A wrong tax code, an old rate, or a taxed item that should be tax-free can all cost you money. To check, multiply the pre-tax subtotal by the tax rate and compare it to the tax line on your receipt. If the store charged more, ask for a refund of the difference. Small gaps of a penny or two are usually just rounding, not a real error. When a coupon or sale price is involved, confirm the discounted subtotal first with the Discount Calculator, and if you are splitting a restaurant bill, the Tip Calculator keeps tax and gratuity straight.

A Quick Mental Shortcut

Move the decimal in your rate and add it to 1. A 7% rate becomes 1.07. A 10% rate becomes 1.10. A 6.5% rate becomes 1.065. Divide your total by that number and you have the pre-tax price. Tracking these totals across a month? Drop them into the Budget Calculator or the Expense Calculator to see where your money goes.


Formulas used

Tax rate as a decimal
r = \frac{\text{Tax Rate}\%}{100}
Original price before tax
\text{Pre-Tax Price} = \frac{\text{Total}}{1 + r}
Tax amount paid
\text{Tax} = \text{Total} - \text{Pre-Tax Price}
Tax actually charged on receipt
\text{Tax Charged} = \text{Total Paid} - \text{Pre-Tax Subtotal}
Expected tax on receipt
\text{Expected Tax} = \text{Pre-Tax Subtotal} \times \frac{r\%}{100}
Overcharge difference
\text{Difference} = \text{Tax Charged} - \text{Expected Tax}
Effective tax rate charged
\text{Effective Rate}\% = \frac{\text{Tax Charged}}{\text{Pre-Tax Subtotal}} \times 100
Price composition share (donut chart)
\text{Share}\% = \frac{\text{Component}}{\text{Pre-Tax Price} + \text{Tax}} \times 100

Frequently asked questions

Why is my answer a penny off from my receipt?

Stores round tax to the nearest cent on each line or on the whole order. Our tool rounds once at the end. That can shift the result by a penny. A one or two cent gap is normal rounding, not an error.

My receipt has taxed and tax-free items. What do I enter?

Only use the taxed part. Add up the taxed items and the tax charged, then enter that smaller total. If you enter the full receipt total, the pre-tax price will be wrong because food, medicine, or clothing may be tax-free in your state.

Are the state rates in the dropdown exact?

No. They are average combined state and local rates. Your city or county rate may be higher or lower. For an exact answer, type the rate printed on your receipt into the tax rate box.

What if my state has no sales tax?

Enter 0 as the rate. The pre-tax price will equal the total and the tax will be $0.00. Alaska, Delaware, Montana, New Hampshire, and Oregon have no state sales tax, but some Alaska towns add a local one.

Does this calculator work for tips or service charges?

No. It only removes a percent that was added on top of the price, like sales tax. If your bill includes a tip or a service fee, subtract those first, then enter what is left.

Can I use this for VAT or GST?

Yes. The math is the same. Divide the total by 1 plus the rate. Enter your VAT or GST rate in the tax rate box and it works the same way.

How do I set a price that ends in a round number after tax?

Enter your target total, like 20.00, and your tax rate. The pre-tax price shown is what you should charge. Add tax to that and the customer pays your round number.

What does the Effective Rate Charged mean in the overcharge checker?

It is the tax you were actually charged divided by the pre-tax subtotal. Compare it to the rate that should apply. If the effective rate is higher, the store used the wrong rate or taxed something it should not have.

The checker says I was undercharged. Do I owe money?

Usually not. The store is responsible for collecting the right tax. A small gap often means some items were tax-free or the store rounded down. You do not need to pay the store more.

How much tax do I get back on a return?

All of it. Enter the total you paid and the tax rate. The tax amount shown is what the store should refund on top of the item price.

Why can't I just subtract 8.25% from my total?

Because tax was added to the smaller pre-tax price, not the total. Subtracting the percent from the bigger number takes off too much. On $108.25 that mistake gives $99.32 instead of the correct $100.00.

Can I save or print my results?

Yes. Use Print / Save as PDF to make a clean copy for records. Use Download CSV to get a spreadsheet file with the total, rate, pre-tax price, tax paid, state, and date.

Does the CSV file include the state I picked?

Yes. It lists the state you chose from the dropdown. If you typed your own rate instead, it lists Custom.

Can I enter a rate with more than two decimals?

Yes. Rates like 8.875% work fine. Type the full rate and the calculator uses every digit in the math.

Why does the tax rate box stop at 100?

A sales tax rate above 100% is not real. The limit blocks typos, like entering 825 instead of 8.25.

What if I know the tax amount but not the rate?

Divide the tax by the pre-tax subtotal, then multiply by 100. Or enter both numbers in the Receipt Overcharge Checker and read the Effective Rate Charged line.

Do the common rate buttons change my state choice?

They only change the rate box. The state dropdown stays as it was. The rate you see in the box is always the one used in the math.

Can I use this for a car purchase?

You can find the pre-tax price, but car deals often add title, tag, and dealer fees that are not taxed the same way. Use the total of the taxed items only for a correct answer.

Is this tool free and does it store my numbers?

It is free with no sign-up. All math runs in your browser and nothing you type is saved or sent anywhere.

What does the donut chart show?

It splits your total into two parts: the original price and the tax. The percent on each slice shows how much of what you paid went to each part.