Sales Tax Calculator
Adding Tax Forward, or Pulling It Back Out
Sales tax calculations run in two directions. Most of the time you know a pre-tax price and want the total at checkout. Occasionally it's the reverse: a receipt shows a total that already includes tax, and you need to know what the pre-tax price and the tax amount actually were. Both are simple algebra, but the reverse direction trips people up because dividing by (1 + rate) is not the same as just subtracting the rate.
The Formula
Extracting Tax: Pre-Tax Price = Total Price ÷ (1 + Rate ÷ 100)
The common mistake in the reverse direction is computing "Total × (1 − Rate)" instead — that undercounts the pre-tax price because the tax rate applies to the smaller pre-tax base, not the larger tax-inclusive total.
Where This Matters
- Checkout estimates — knowing the final price before you reach the register, especially for larger purchases.
- Expense reporting — separating the tax portion out of a total receipt amount for accounting or reimbursement.
- Cross-state comparisons — sales tax rates vary widely by state and even by city or county, so the same purchase can cost noticeably different amounts depending on where it's made.
$250 Purchase at Common U.S. Sales Tax Rates
| Tax Rate | Tax Amount | Total Price |
|---|---|---|
| 4% | $10.00 | $260.00 |
| 6% | $15.00 | $265.00 |
| 7.25% | $18.12 | $268.12 |
| 8.875% | $22.19 | $272.19 |
Five U.S. states — Alaska, Delaware, Montana, New Hampshire, and Oregon — charge no statewide sales tax; all others set their own combined state-and-local rates.
How to Use This Calculator
- Choose Add Sales Tax to Price or Extract Tax from Total Price.
- Enter the Price (pre-tax) or Total Price (tax-inclusive), depending on the mode.
- Enter the Sales Tax Rate as a percentage.
- Select Calculate to see the resulting total or pre-tax price.
Related Calculations
For value-added tax used outside the U.S., see the VAT Calculator, or check the Discount Calculator to combine a sale price with tax.