How do you calculate sales tax if it is 8.25 percent in Texas?

To calculate sales tax in Texas at a rate of 8.25 percent, first determine the taxable amount of the purchase. Multiply this amount by 0.0825 (which represents 8.25 percent). For example, if the purchase is $100, the sales tax would be $100 x 0.0825 = $8.25. Finally, add the sales tax to the original purchase price to find the total amount due.