Reverse Sales Tax Calculator
Calculate pre-tax price and tax amount from any total using a known sales tax rate.
Useful for expense reporting, accounting, and verifying receipts.
Reverse sales tax calculation finds the original pre-tax price when you only know the final total you paid. This is useful for reimbursements, accounting entries, price comparisons, and any situation where you need to separate the tax from the total.
Formula: Pre-Tax Price = Total Price ÷ (1 + Tax Rate)
Tax Amount Paid: Tax Paid = Total Price − Pre-Tax Price
Or directly: Tax Paid = Total Price × (Tax Rate ÷ (1 + Tax Rate))
What each variable means:
- Total Price — the final amount charged, including tax (what appears on your receipt).
- Tax Rate — the sales tax percentage as a decimal (e.g., 8.5% = 0.085).
- Pre-Tax Price — the base price before tax was applied.
Why you can’t just subtract the rate percentage: A common mistake is subtracting 8% from the total to get the pre-tax price. This is wrong because the tax was calculated on the pre-tax price — so dividing the total by (1 + rate) is necessary.
Worked example: You paid $54.00 at a store in a city with 8% sales tax.
Pre-Tax Price = $54.00 ÷ 1.08 = $50.00 Tax Paid = $54.00 − $50.00 = $4.00
Verify: $50.00 × 0.08 = $4.00 ✓
Common U.S. state sales tax rates (2024):
- No state sales tax: Oregon, Montana, New Hampshire, Delaware, Alaska
- Low (under 5%): Hawaii 4%, Wisconsin 5%, Maine 5.5%
- Mid (6–7%): Texas 6.25%, Georgia 4%, California 7.25% (state only)
- High (with local): Tennessee 9.55%, Louisiana 9.55%, Arkansas 9.47%
Local taxes can add 1–5% on top of state rates. The combined rate for your specific location matters.