Price after Sales Tax and Discount

Price after Sales Tax and Discount

How to find the price after sales tax and discount: formula, example, and its solution.

Formula

(final) = (price)[1 + (sales tax rate)][1 - (discount rate)]

(final) = (price)[1 + (sales tax rate)][1 - (discount rate)]

(final): Price after sales tax and discount
(price): Original price

By using this formula,
you can directly find the final price
after sales tax and discount.

The order of applying
[sales tax rate] and [discount rate]
doesn't matter, because
(price)[1 + (sales tax rate)][1 - (discount rate)]
= (price)[1 - (discount rate)][1 + (sales tax rate)].

Let's see why this is true.

(price)[1 + (sales tax rate)]
is [price after sales tax].

Price after sales tax - Formula

Then, apply the discount rate on this price:
[price after sales tax][1 - (discount rate)].

Price after discount - Formula

Then
(final) = (price)[1 + (sales tax rate)][1 - (discount rate)].

Example

The original price of a product is $100. If the sales tax rate is 10%, and if the product is on sale for 20%, find the final price.

(original price) = 100
(sales tax rate) = 0.10
(discount rate) = 0.20

So (final) = 100(1 + 0.10)(1 - 0.20)
= 88.

The unit of the price is $.

So write the answer with its unit: $88.