Sales tax on $500 at 7%

Sales tax math has two directions, and this calculator handles both. In the default forward mode, you enter a pre-tax price and a tax rate, and the calculator adds tax on top using tax = price × (rate ÷ 100), then total = price + tax. In reverse mode, you enter a total price that already includes tax — like the amount on a receipt — and the calculator backs out how much of that total was tax using pretax = total ÷ (1 + rate ÷ 100).

The reverse calculation is the one people get wrong most often, because it's tempting to just multiply the total by the tax rate and subtract — but that overstates the tax. Dividing by (1 + rate ÷ 100) first removes the tax correctly, since the tax rate percentage in the original math was calculated against the pre-tax price, not the total.

Sales tax in the United States isn't a single national rate — it's set at the state level, and most states also allow counties and cities to add their own local sales tax on top of the state rate. That means the effective combined rate can vary significantly even within the same state; two neighboring cities can have noticeably different total sales tax rates on the same purchase.

Five states — Oregon, Montana, New Hampshire, Delaware, and Alaska — don't charge a statewide sales tax at all (Alaska allows local municipalities to levy their own sales taxes, so some purchases there are still taxed). This calculator's reference table shows a handful of illustrative state rates, but always check your specific city or county's combined rate for an exact number.

This tool calculates tax based on the state (or combined) rate you enter yourself — it doesn't look up your location automatically and doesn't account for product-specific exemptions, which many states apply to groceries, prescription medication, or clothing. For an exact tax amount on a real purchase, check your state and local tax authority's current combined rate and any applicable exemptions.