What is a sales tax calculator?
A sales tax calculator finds either the tax dollars from a pretax subtotal or backs out the pretax amount from a tax-inclusive receipt—given a combined rate. Real life adds wrinkles: some goods are exempt, some jurisdictions tax services differently, and marketplaces may remit for third-party sellers. This tool focuses on clear math you can combine with local rules. Pair with our tip calculator (gratuity on food) and discount calculator (coupons before tax in many states).
How to use this sales tax calculator
- Confirm whether your amount is pretax or tax-included—register totals after “+ tax” need the reverse mode.
- Enter the combined state + local rate expressed as a percent for your transaction’s situs (ZIP/city).
- Subtract exempt items mentally when needed—grocery exemptions do not apply uniformly.
How to calculate sales tax manually
Tax = pretax × (rate ÷ 100). Total = pretax + tax. Example: $84.00 pretax at 7.75% → 84 × 0.0775 = 6.51 tax → $90.51 out the door.
To strip tax from a tax-included price: pretax = total ÷ (1 + rate/100). Example: $107.50 all-in at 7.5% → 107.50 ÷ 1.075 ≈ $100.00 pretax.
| Direction | Operation |
|---|---|
| Add tax | total = subtotal × (1 + r/100) |
| Remove tax | subtotal = total ÷ (1 + r/100) |
Reference: why rates differ so much
Most US receipts show a stack of state, county, city, transit, and special-purpose district add-ons—always look up the exact point of sale.
| Locale | Approx. | Notes |
|---|---|---|
| Delaware | 0% | No state sales tax |
| California (varies) | ~7.25%–10.75%+ | State + district + city stack |
| New York (NYC) | ~8.875% | State + MCTD + city |
| Texas (state) | 6.25% | Locals add on top |
Checkout tips
Manufacturer coupons applied before scan usually reduce taxable amount; post-tax cashback rewards do not. When in doubt, read the receipt’s subtotal lines—they reveal what the POS treated as taxable.
Marketplace facilitators (major e-commerce) may collect “estimated” tax; year-end true-ups happen rarely for consumers but matter for sellers filing returns.
More detail in Frequently Asked Questions.