Reverse Sales Tax Calculator
Find the original price before sales tax was added from the total amount
Enter the total amount you paid including sales tax
Enter your combined state and local sales tax rate
Original Price (Before Tax)
Tax paid: at % rate
Pre-Tax Price
Original cost
Tax Amount
% of total
Total Paid
Amount verified
Price Breakdown
Original Price
(%)
Sales Tax
(%)
Verification
× (1 + %) =
This confirms the pre-tax price calculation is correct
Calculation Summary
| Total Paid | |
| Tax Rate | % |
| Tax Amount | |
| Pre-Tax Price |
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About Reverse Sales Tax Calculator
What is a Reverse Sales Tax Calculator?
A reverse sales tax calculator helps you find the original price of an item before sales tax was added when you only know the total amount paid. This is useful when you need to determine the pre-tax cost for expense reports, budgeting, or understanding how much of your payment went to taxes.
How to Use This Calculator
- Enter Total Price: Input the total amount paid (including tax)
- Set Tax Rate: Enter your local sales tax rate or use a preset button
- View Results: See the pre-tax price, tax amount, and breakdown instantly
Understanding Your Results
Pre-Tax Price
The original price of the item before sales tax was added. This is calculated by dividing the total by (1 + tax rate).
Tax Amount
The portion of your total payment that went to sales tax. This equals the total minus the pre-tax price.
Effective Tax Percentage
Shows what percentage of your total payment was sales tax (always slightly less than the tax rate itself).
The Formula Behind the Calculation
Reverse Sales Tax Formula:
- Pre-Tax Price = Total Price ÷ (1 + Tax Rate ÷ 100)
- Tax Amount = Total Price - Pre-Tax Price
Example: If you paid $108.00 total with an 8% tax rate:
- Pre-Tax Price = $108.00 ÷ 1.08 = $100.00
- Tax Amount = $108.00 - $100.00 = $8.00
Source: Standard reverse sales tax computation used by accountants and tax professionals.
When to Use Reverse Tax Calculations
| Scenario | Example Use |
|---|---|
| Expense Reports | Separate tax from receipts |
| Business Deductions | Calculate deductible vs tax amounts |
| Price Comparisons | Compare pre-tax prices across locations |
| Budget Planning | Understand true product costs |
| Tax Documentation | Verify sales tax on invoices |
Frequently Asked Questions
Why is reverse tax calculation different from regular tax?
When you add tax, you multiply by the rate. To reverse it, you divide by (1 + rate) instead of simply subtracting the rate percentage.
How do I verify the calculation is correct?
Multiply the pre-tax price by your tax rate and add it back. Example: $100.00 × 1.08 = $108.00 total.
What if I don't know the tax rate?
Check your receipt for the tax line item, or look up your state and local combined sales tax rate.
Why doesn't subtracting the tax percentage work?
Because tax is calculated on the original price, not the total. If you paid $108 at 8%, the tax was 8% of $100 (not 8% of $108).
Common Combined Tax Rates by State
| State | Average Combined Rate |
|---|---|
| California | 8.68% |
| Texas | 8.19% |
| New York | 8.52% |
| Florida | 7.02% |
| Illinois | 8.81% |
| Pennsylvania | 6.34% |
| Ohio | 7.22% |
| Washington | 9.29% |
Combined rates include state + average local taxes.
Disclaimer: This calculator provides estimates for informational purposes only. Tax rates vary by location and change frequently. Consult your local tax authority for official rates.
Quick Tips
💡 Finding Your Tax Rate
- • Check your receipt for the tax line
- • Look up your state + local combined rate
- • Some purchases have special rates
⚠️ Common Mistakes
- • Don't just subtract the tax percentage
- • Use the correct combined rate
- • Verify with the formula shown above