A base price is the price for any standard commodity before applying discounts and extras. Say, for example, you want to calculate the price of an item so the final sale price, including sales tax, will come to a full dollar amount, with no cents. If you apply a little reverse engineering, you will find the base price.

Know Your Amounts

Identify the final price of the item, with all sales tax included. Also identify the sales tax rate -- for example, 7 percent.

Do the Math

Divide the grand total of the item by 1 plus the sales tax percentage. If, for example, your total is $10 and your sales tax equals 7 percent, your base price is $9.35. Use an online base price calculator to check your math.