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Sales tax & VAT / Reverse Sales Tax Calculator

Reverse Sales Tax Calculator

Work back from a total that already includes sales tax to the price before tax and the tax amount, at any rate.
$

Enter a number of at least 0

%

Enter a number from 0 to 30%

Use the full combined rate: state plus city and county.

Price before tax
$80.00
$6.40sales tax
7.41%tax share of total
$0total $86.40
  • Price
  • Sales tax
Total including tax$86.40
Sales tax · 8% of $80.00−$6.40
Price before tax$80.00

Divide by 1.08, not multiply by 0.92: taking 8% off the total removes too much.

See breakdown

How the reverse sales tax calculation works

  1. Turn the rate into a multiplier

    Add 1 to the rate as a decimal. An 8% rate becomes 1.08.

  2. Divide the total by the multiplier

    $86.40 ÷ 1.08 = $80.00. That is the price before tax.

  3. Subtract to get the tax

    $86.40 − $80.00 = $6.40 of sales tax.

  4. Don't subtract the rate from the total

    8% of $86.40 is $6.91, which is too much. The tax was charged on $80, not on $86.40.

Worked example. A receipt total of $86.40 at an 8% rate splits into an $80.00 price and $6.40 of sales tax.

Reverse Sales Tax FAQ

How do I calculate the price before tax from a total?

Divide the total by 1 plus the tax rate. At 8%, $86.40 ÷ 1.08 = $80.00.

How do I find the sales tax included in a price?

Work out the pre-tax price first, then subtract it from the total. $86.40 − $80.00 = $6.40.

Why can't I just take the tax percent off the total?

The tax was charged on the smaller pre-tax price. Taking 8% off $86.40 removes $6.91 instead of $6.40.

What is the reverse sales tax formula?

Price before tax = total ÷ (1 + tax rate as a decimal), and sales tax = total − price before tax. At 8.25%, $54.13 ÷ 1.0825 = $50.00, so the tax is $4.13.

How do I back out sales tax from a receipt?

Take the total including tax and divide it by 1 plus the combined rate. The result is the pre-tax price; the rest is tax. The tax on the receipt was rounded to the cent, so a back-calculated price can be off by a cent.

What share of the total is sales tax?

Rate ÷ (1 + rate). At 8%, 0.08 ÷ 1.08 = 7.41% of the total is tax, which is why taking 8% off the total removes too much.

How do I find the tax rate from the total and the price?

Divide the total by the pre-tax price and subtract 1. $86.40 ÷ $80.00 − 1 = 0.08, an 8% rate.

What rate should I use?

Use the combined rate shown on the receipt or for the place of sale: state plus any city, county and district tax.

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