Why can't I just subtract the tax percentage from the total?

Because the tax percentage was calculated on the original price, not on the final total. Subtracting a percentage of the total gives a different, larger deduction than the actual tax added, so dividing by (1 + rate) is the correct way to undo it.

Where do I find my local sales tax rate?

Sales tax rates are set at the state level and are often stacked with additional county or city rates, so the combined rate can vary within the same state. Your state's department of revenue website usually has the most current official rate.

Does this work if multiple items with different tax rates are on one receipt?

Not directly. This calculator assumes a single total taxed at one flat rate. If a receipt mixes taxable and tax-exempt items, those totals need to be separated first and reverse-calculated individually.

Can I use this to figure out how much tax I can deduct or claim back?

This calculator only splits a total into price and tax. It does not account for specific deduction rules, exemptions, or filing situations, which should be checked with an accountant or local tax authority.

Free Reverse Sales Tax Calculator

Got a receipt or credit card charge that already includes tax, and need to work backward? This reverse sales tax calculator takes your total price and the sales tax rate and instantly tells you the original price before tax and exactly how much of that total was tax.

Looking for something else? Explore more free tools in our Mortgage Calculator, Loan Calculator and Auto Loan Calculator calculators — or browse our full calculator library to find exactly what you need.

Reverse Sales Tax Calculator

Enter the total price you paid (with tax already included) and the sales tax rate.

Quick Formula Reference

Value	Formula
Sales Tax Rate	Sales Tax Percent ÷ 100
Price before Tax	Total Price with Tax ÷ (1 + Sales Tax Rate)
Sales Tax Amount	Price before Tax × Sales Tax Rate

Your price before tax and the tax amount will appear here once you calculate.

How to Calculate Sales Tax From a Total Price

Most of the time, sales tax works forward: you know a price, you add tax, and you get a total. But every so often you're stuck with only the final number — a credit card charge, a receipt total, a budget figure — and you need to peel the tax back off to find the original price. That's exactly what "reverse" sales tax means, and it only takes three steps.

Step 1: Turn the Tax Percentage Into a Decimal

Sales Tax Rate = Sales Tax Percent ÷ 100

Step 2: Divide the Total by 1 Plus the Tax Rate

This is the key step people get wrong — you can't just subtract the tax percentage from the total, because that percentage was applied to the original price, not the total. Dividing by (1 + rate) correctly undoes the tax:

Price before Tax = Total Price with Tax ÷ (1 + Sales Tax Rate)

Step 3: Work Out the Tax Amount

Sales Tax = Price before Tax × Sales Tax Rate

Worked Example

Say your credit card was charged $858 total for a new phone, and your state sales tax rate is 7.25%:

Step 1: 7.25 ÷ 100 = 0.0725
Step 2: $858 ÷ 1.0725 = $800.00 (price before tax)
Step 3: $800.00 × 0.0725 = $58.00 (tax paid)

Add them back together — $800.00 + $58.00 = $858.00 — and you're right back to the total, which is a quick way to double-check your own math too.

A Quick Note on Rounding

Store receipts round the tax to the nearest cent at the register, so if you reverse-calculate from a real receipt, your result might land a cent or two off from what's printed. That's normal rounding, not a mistake in the formula.

Frequently Asked Questions (FAQs)

Because the tax percentage was calculated on the original price, not on the final total. Subtracting a percentage of the total gives you a different, larger deduction than the actual tax that was added, so the result comes out wrong. Dividing by (1 + rate) is the correct way to undo it.

Sales tax rates are set at the state level, and often stacked with additional county or city rates on top, so the combined rate can vary a lot even within the same state. Your state's department of revenue website usually has the most current, official rate for your exact location.

Not directly. This calculator assumes a single total taxed at one flat rate. If your receipt mixes taxable and tax-exempt items, or different tax categories, you'll need to separate those totals first and reverse-calculate each one individually.

Most registers round the tax to the nearest cent at checkout, while this calculator works with the exact decimal value. Over a single transaction that difference is usually a cent or two at most, and is completely normal.

This calculator only splits a total into price and tax — it doesn't know your specific tax deduction rules, exemptions, or filing situation. For anything related to tax refunds, deductions or filing, check with your accountant or your local tax authority.

Disclaimer: This calculator provides a general estimate based on the rate you enter and is not a substitute for official tax advice. Sales tax rates and rules vary by state, county and city, and can change over time — always confirm the exact rate and any exemptions with your local tax authority for anything that matters financially.

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