When you know the total amount that includes sales tax and want to find out the original price before tax, you have to calculate sales tax backwards. There can be various reasons for doing this, such as determining the pre-tax price of an item or verifying that the correct amount of tax was applied to a purchase. In this article, we will break down the process of calculating sales tax backwards from the total in a few easy-to-follow steps.

Step 1: Determine the Sales Tax Rate

The first thing you need to do is find out the sales tax rate for the location where the purchase was made. Sales tax rates can vary by state, county, and city, so it’s essential to look up this information before performing any calculations.

Step 2: Convert the Sales Tax Rate to a Decimal

Convert the sales tax percentage rate to a decimal by dividing it by 100. For example, if your sales tax rate is 7%, you would divide 7 by 100 to get 0.07 in decimal form.

Step 3: Add 1 to the Sales Tax Rate Decimal

Next, add 1 to your sales tax rate decimal. Continuing with our example of a 7% sales tax rate, adding 1 would result in a value of 1.07 (1 + 0.07).

Step 4: Divide the Total Amount by the Result from Step 3

Now, take your total amount that includes sales tax and divide it by your result from step 3. For example, suppose your total amount including sales tax is $107. Dividing $107 by your result of 1.07 will give you approximately $100 as your pre-tax price.

Step 5: Calculate Sales Tax Amount

Finally, subtract the pre-tax price obtained in step 4 from the total amount including sales tax to find the actual sales tax amount. In our example, subtracting $100 from $107 gives us a sales tax amount of $7.

And that’s it! You have now successfully calculated sales tax backwards from the total. By understanding this process, you’ll be able to quickly and easily determine the pre-tax price and sales tax amount from a total that includes tax, allowing you to make more informed decisions about your purchases and verify that the correct amount of tax has been applied.