How to Calculate Sales Tax (2026)

Sales tax is a percentage added to the price of goods or services at the point of sale. In the US, rates vary by state — and often by county or city — so knowing the applicable rate is the first step. The formula is simple: multiply the pre-tax price by the tax rate, then add the result to the original price to get the total.

The Formula

Tax amount = price × (rate ÷ 100). Total = price + tax amount. For example, a $45 item in a state with 8% sales tax: tax = $45 × 0.08 = $3.60, so the total is $48.60. If you only have the total and need to work backwards to find the pre-tax price, divide by (1 + rate): pre-tax = total ÷ 1.08 = $44.44 (rounded).

Use the Tax Calculator to do this instantly — enter the price and rate, and it returns the tax amount and total in one step.

US Sales Tax Rates by State

The US has no federal sales tax. Each state sets its own base rate, and local jurisdictions often add on top. The table below shows the state base rates for the most populous states; actual rates at the register can be higher once city and county surcharges are included.

Oregon and Montana are among the five states with no state-level sales tax. Always verify the current rate for your specific city and county — local add-ons can push the combined rate well above the state base.

Common Mistakes

Applying the wrong rate is the most common error — using the state base rate when a local surcharge applies, or vice versa. A second mistake is forgetting that some goods are exempt: groceries and prescription drugs are tax-exempt in many states, while prepared food and clothing may be taxed differently. When calculating tax for a mixed basket, split the items by category and apply the relevant rate to each group, then sum.