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Reverse Sales Tax Calculator
Your total price
Example: $108.00 total at 8% tax → $100.00 pre-tax price, $8.00 tax.
Behind the numbers
How the pre-tax price is calculated
The total you paid already includes tax, so you cannot just subtract the rate from the total — that would understate the pre-tax price. The total equals the pre-tax price plus tax on that price, so total = pre-tax × (1 + rate). Turn the formula around to get pre-tax = total ÷ (1 + rate), then tax = total − pre-tax. The calculator does that division for any total and any tax rate, including combined state and local rates.
Total $108.00 at 8%: pre-tax = $108.00 ÷ (1 + 0.08) = $108.00 ÷ 1.08 = $100.00. Tax = $108.00 − $100.00 = $8.00. Check it forward: $100.00 × 8% = $8.00 tax, and $100.00 + $8.00 = $108.00 total.
Examples
Examples
| Total including tax | Tax rate | Pre-tax price | Tax amount |
|---|---|---|---|
| $54.00 | 8% | $50.00 | $4.00 |
| $108.00 | 8% | $100.00 | $8.00 |
| $216.00 | 8% | $200.00 | $16.00 |
| $107.00 | 7% | $100.00 | $7.00 |
| $110.00 | 10% | $100.00 | $10.00 |
| $162.00 | 8% | $150.00 | $12.00 |
Tips before you use it
Use the full combined rate — state plus county plus city — if the receipt shows one total tax figure.
Do not subtract 8% from $108: 8% of $108 is $8.64, which gives the wrong pre-tax price of $99.36.
For business expenses, the pre-tax price is usually the deductible amount; keep the receipt and note the rate you used.
Round to the nearest cent at the end, not in the middle, so the pre-tax price and tax still add up to the total.
Good to know
Frequently asked questions
How do I find the price before tax?
Divide the total by 1 plus the tax rate as a decimal. At 8%, divide by 1.08. At 7%, divide by 1.07. The result is the pre-tax price, and the total minus that price is the tax.
Why can I not just take 8% off the total?
Because the 8% tax was charged on the pre-tax price, not on the total. Taking 8% off the total charges tax on the tax as well, so the answer comes out too low.
What if the tax rate includes state and local tax?
Add the rates together first, then use the combined rate in the same formula. For example, a 6% state rate plus a 2% local rate is an 8% combined rate.
Does this work for VAT as well?
Yes, the math is the same for any tax added as a percentage of the pre-tax price. Enter the VAT rate as the tax rate and the VAT-inclusive total as the total.