How do you remove sales tax from a total?
Divide the tax-inclusive total by (1 + rate/100) to get the pre-tax amount.
Reverse Sales Tax Calculator
Start from a tax-inclusive total and recover the pre-tax price and tax portion.
Enter total with tax
Provide the tax-inclusive total and the sales tax rate that was applied.
About this calculator
How to use Reverse Sales Tax Calculator, plus the formulas and logic behind the results.
Tool description
When a receipt shows only the final total, reverse sales tax divides out the embedded tax using the known rate.
How to use
- Enter the total amount that includes sales tax.
- Enter the sales tax rate that was used.
- Select Calculate to view pre-tax amount and tax.
- Cross-check against the Sales Tax Calculator in the forward direction.
Formulas & reference
Pre-tax = total ÷ (1 + rate ÷ 100)Tax = total − pre-tax
Reverse tax examples
- $107.25 at 7.25% → ~$100 pre-tax, ~$7.25 tax
- Pre-tax × (1 + rate) should rebuild the total
- Use the same rate that was charged originally
- Pair with Sales Tax Calculator to verify
Calculation logic
Divides the inclusive total by (1 + rate). A 100%+ rate that would make the divisor invalid is rejected.
Assumes a single flat rate on the whole amount. Compounded or multi-rate tickets may not reverse cleanly.
Reverse Sales Tax Calculator FAQ
Common questions about the calculation and how to interpret the estimate.
Why not multiply by the rate?
That would double-count. The tax is already inside the total, so you divide it out.
What if I don’t know the rate?
Look up the rate for that purchase location; reverse math needs the rate.
Will rounding match my receipt?
Minor cent differences can appear from store rounding rules.
Is this the same as VAT extract?
Similar idea; use VAT Calculator for VAT-labeled net/gross workflows.
Is this tool free?
Yes—free online calculator with guide and FAQ on this page.