Reverse sales tax calculator
Reverse Sales Tax Calculator 2026
Work backward from a tax-included total to estimate the pre-tax price and sales tax amount. Choose a verified state base preset or enter a local rate.
Quick answer
An $108.25 tax-included total at 8.25% reverses to $100 before tax and $8 sales tax. The forward check adds back to $108.
Reverse sales tax formula
Pre-tax price = total after tax / (1 + tax rate / 100). Sales tax = total after tax - pre-tax price. Quantity only divides the totals into per-unit amounts.
State and local rate caution
The available presets are state base rates only. Cities, counties, districts, product categories, exemptions, and destination rules may change the combined rate. Enter the current local rate when you know it.
Verified state base presets
| Preset | Rate | Last verified |
|---|---|---|
| California state base | 7.25% | 2026-07-30 |
| Texas state rate | 6.25% | 2026-07-30 |
Local rates may differ. This is a planning estimate, not a sales tax filing or tax advice.
Common questions
How do I reverse calculate sales tax?
Divide the tax-included total by 1 plus the tax rate as a decimal. For an 8.25% rate, pre-tax price = total / 1.0825; sales tax is the difference.
Does this use state or local sales tax?
The presets are verified state base rates only. Local, county, district, destination, product, and marketplace rules can change the combined rate.
What is the difference between tax-inclusive and pre-tax price?
A tax-inclusive total already contains sales tax. Reverse calculation separates it into an estimated pre-tax amount and tax amount.
Does quantity change the sales tax rate?
No. Quantity only divides the estimated totals into per-unit amounts. The calculator assumes the same tax treatment for every unit.
Is this a sales tax filing calculator?
No. It is a planning estimate. Confirm taxable status, sourcing, exemptions, rounding, and current local rates with the relevant tax authority or adviser.