Price Before Tax is designed for the exact search intent behind “reverse sales tax calculator”. Work backward from a tax-included total to recover the original pre-tax price and the tax amount. Recover the base price from an already-taxed total. Reverse sales-tax formula Pre-tax price = total ÷ (1 + rate/100) . Then tax amount = total − pre-tax price . Why simple subtraction is wrong The tax percentage was applied to the smaller pre-tax amount, not to the final tax-inclusive total. Subtracting the same percentage from the total therefore gives the wrong base price. Use the correct combined rate Enter the actual rate that produced the receipt total. The calculator does not establish which jurisdictional rate should apply unless that lookup is explicitly supported. Worked example: $108 ÷ 1.08 = $100 pre-tax, and the tax amount is $8. Common practical uses include Split receipt totals; Recover invoice subtotals; Check bookkeeping entries; Compare tax-inclusive and pre-tax pricing. Important limitations: An incorrect entered rate produces an incorrect pre-tax amount. Real-world tax rules can include exemptions or multiple tax components. The tool performs reverse percentage math, not tax-law determination. Key questions this page should answer include: How do I remove sales tax from a total? Divide the tax-inclusive total by 1 plus the tax rate as a decimal. Why can't I just subtract the tax percentage? Because the tax was calculated on the pre-tax price, not on the final total. What is the pre-tax price of $108 at 8% tax? $100. How do I find the tax amount after reversing it? Subtract the recovered pre-tax price from the final total. Does this work for tax-inclusive VAT or GST? The reverse percentage formula is mathematically similar, but local tax rules and invoice conventions can differ. The page should stay focused on this differentiator: Make the division-not-subtraction distinction the central differentiator. The tool should appear before the explanatory copy so a visitor can complete the task immediately, then use the supporting content to verify the method and understand the result.
How to use this tool
Reverse sales-tax formula
Pre-tax price = total ÷ (1 + rate/100). Then tax amount = total − pre-tax price.
Why simple subtraction is wrong
The tax percentage was applied to the smaller pre-tax amount, not to the final tax-inclusive total. Subtracting the same percentage from the total therefore gives the wrong base price.
Use the correct combined rate
Enter the actual rate that produced the receipt total. The calculator does not establish which jurisdictional rate should apply unless that lookup is explicitly supported.
Examples
Reverse 8% tax from $108
$108 ÷ 1.08 = $100 pre-tax, and the tax amount is $8.
Common use cases
- Split receipt totals
- Recover invoice subtotals
- Check bookkeeping entries
- Compare tax-inclusive and pre-tax pricing
Frequently asked questions
How do I remove sales tax from a total?
Divide the tax-inclusive total by 1 plus the tax rate as a decimal.
Why can't I just subtract the tax percentage?
Because the tax was calculated on the pre-tax price, not on the final total.
What is the pre-tax price of $108 at 8% tax?
$100.
How do I find the tax amount after reversing it?
Subtract the recovered pre-tax price from the final total.
Does this work for tax-inclusive VAT or GST?
The reverse percentage formula is mathematically similar, but local tax rules and invoice conventions can differ.