How do I reverse sales tax?
Enter the total you paid and the sales tax rate to see the price before tax and how much of the total was tax. Or enter the total and the price to find the rate.
- Price before tax
- $100.00
A total of $108.25 with 8.25% sales tax is a price of $100.00 before tax, plus $8.25 of tax.
- Sales tax
- $8.25
Price before tax: $100.00. A total of $108.25 with 8.25% sales tax is a price of $100.00 before tax, plus $8.25 of tax.
The results are estimates for information only. They are not financial, tax, or legal advice. Check the numbers with your lender or a qualified professional before you decide. Terms of use
How to calculate
Works back from a total that includes sales tax to the price before tax and the tax paid, or finds the tax rate from the total and the price.
Example with the default inputs (Total with tax $108.25, Sales tax rate 8.25%): A total of $108.25 with 8.25% sales tax is a price of $100.00 before tax, plus $8.25 of tax.
Formula: price before tax = total × 100 ÷ (100 + rate); tax = total − price before tax; rate = tax ÷ price before tax × 100.
- One sales tax rate applies to the whole total. Items taxed at different rates, and fees that are not taxed, are not included.
- Arithmetic is exact on the typed decimals; money shows to the cent, halves up.
- Stores round the tax on a receipt to the cent, so a price worked back from a total can be a fraction of a cent off the shelf price.
Worked examples
Each example is checked against the calculator on every build.
- Total with tax $417.48, Sales tax rate 6.5% gives Price before tax $392.00, Sales tax $25.48.Source: OpenStax, Prealgebra 2e, section 6.3 "Solve Sales Tax, Commission, and Discount Applications" (https://openstax.org/books/prealgebra-2e/pages/6-3-solve-sales-tax-commission-and-discount-applications), Example 6.25 worked back: 417.48 ÷ 1.065 = 392
- Price before tax $499.00, Sales tax $42.42 gives Sales tax rate 8.501002%, Total with tax $541.42.Source: OpenStax, Prealgebra 2e, section 6.3 "Solve Sales Tax, Commission, and Discount Applications" (https://openstax.org/books/prealgebra-2e/pages/6-3-solve-sales-tax-commission-and-discount-applications), Example 6.26: 42.42 ÷ 499 = 8.5% (rounded there; exactly 8.501002…%)
- Total with tax $100.00, Sales tax rate 8.25% gives Price before tax $92.38, Sales tax $7.62.
- Total with tax $108.25, Price before tax $100.00 gives Sales tax rate 8.25%, Sales tax $8.25.
How it works
A total with sales tax is the price before tax plus a percent of that price. With the total T, the tax rate r (in percent), the price before tax P and the tax X:
- Price before tax P = T × 100 ÷ (100 + r)
- Tax X = T − P, which is also P × r ÷ 100
- Total T = P × (100 + r) ÷ 100 = P + X
- Tax rate r = X ÷ P × 100 = (T − P) ÷ P × 100
Fill in any two of the four, and the calculator works out the other two. If you fill in more, they must agree.
Rules:
- The total and the price before tax are more than $0 and at most $1 trillion. The tax is $0 to $1 trillion. The rate is 0% to 100%. A worked-out value outside these limits has no answer.
- A price before tax larger than the total has no answer (the tax would be negative).
- A tax equal to or larger than the total has no answer (the price would be $0 or less).
- A rate above 100% has no answer.
- From a tax and a 0% rate there is no answer, because any price has $0 tax at 0%.
- The arithmetic is exact on the decimals you type. Money shows to the cent, with halves rounded up (away from 0). The rate shows up to 4 decimals.
Assumptions
- One rate applies to the whole total. Items taxed at other rates and untaxed fees are not included.
- Stores round the tax on a receipt to the cent, so a worked-back price can differ from the shelf price by a fraction of a cent.
Worked examples by hand
$417.48 at 6.5%. P = 417.48 × 100 ÷ 106.5 = $392, and X = 417.48 − 392 = $25.48.
$42.42 of tax on a $499 price. r = 42.42 ÷ 499 × 100 = 8.501002…%, shown as 8.501% (the textbook rounds it to 8.5%), and T = 499 + 42.42 = $541.42.
$100 at 8.25%. P = 100 × 100 ÷ 108.25 = 92.3787528868…, shown as $92.38. X = 100 − 92.3787528868… = 7.6212471131…, shown as $7.62.
$108.25 with a $100 price. r = (108.25 − 100) ÷ 100 × 100 = 8.25%, and X = $8.25.
Other questions people ask
How do I take sales tax out of a total?
Divide the total by 1 plus the tax rate as a decimal. A total of $108.25 at 8.25% is 108.25 ÷ 1.0825 = $100 before tax, and $8.25 of tax.
Why can I not just take the tax percent off the total?
Because the tax was a percent of the lower price, not of the total. 8.25% of $108.25 is $8.93, which is more than the $8.25 of tax that was added. Dividing by 1.0825 gives the right price.
How do I find the sales tax rate from a receipt?
Divide the tax by the price before tax and multiply by 100. $42.42 of tax on a $499 purchase is 42.42 ÷ 499 × 100 = 8.501%, which a receipt rounds to 8.5%.
Why is the price a fraction of a cent off?
Stores round the tax on each receipt to the cent. Working back from a rounded total can give a price like $92.3788, which shows as $92.38. The exact price on the shelf is the nearest amount that gives your total.
What rate should I use?
Use the full rate you paid: the state rate plus any county and city rates. The rate is printed on most receipts, or your state revenue department lists the local rates.
Does this work for VAT or GST?
Yes. VAT and GST included in a price work the same way: divide the price by 1 plus the rate. Enter the VAT or GST rate as the tax rate.