The basic sales tax formula
To calculate sales tax, multiply the taxable purchase price by the sales tax rate expressed as a decimal.
For example, a 7% sales tax rate is written as 0.07 when used in the calculation.
Example
If a taxable purchase costs $100 and the applicable sales tax rate is 7%, the sales tax would be $7 and the total would be $107.
Actual sales tax rules can vary depending on location, product type, exemptions, and other applicable rules.
State and local sales taxes
In many locations, the applicable rate can include both state and local components. The combined rate depends on where the purchase is made and the applicable tax rules.