A sale tag might show the old price and the new price but not the discount, or the discount but not the final price. This guide shows how to calculate discount percentage from two prices, how to find the sale price from a discount, and how stacked discounts really add up.

Discount percentage formula

The discount is the difference between the original (marked) price and the sale price. To turn it into a percentage, divide by the original price:

Discount % = (Original price − Sale price) ÷ Original price × 100

How to calculate discount percentage step by step

1. Subtract the sale price from the original price to get the discount amount.
2. Divide the discount amount by the original price.
3. Multiply by 100.

Discount percentage example

A jacket was 2,500 and is now 1,875. The discount is 625, so the discount percentage is 625 ÷ 2,500 × 100 = 25 percent.

How to find the sale price from a discount

When you know the discount percentage, multiply the original price by what you still pay:

Sale price = Original price × (1 − Discount % ÷ 100)

25 percent off 2,500 is 2,500 × 0.75 = 1,875. You save 2,500 − 1,875 = 625.

The discount calculator gives the sale price and your savings at once, including a second stacked discount.

How to find the original price

If you only see the sale price and the discount, divide: Original = Sale price ÷ (1 − Discount % ÷ 100). A sale price of 1,875 at 25 percent off means the original was 1,875 ÷ 0.75 = 2,500.

Successive discounts

“20 percent off, then an extra 10 percent off” is not 30 percent. Each discount applies to the already-reduced price:

Remaining = 0.80 × 0.90 = 0.72 ⇒ Total discount = 28%

On a 2,500 item, that means paying 1,800, not 1,750.

Discount percentage reference

Original	Sale price	Discount	Discount %
100	80	20	20%
2,500	1,875	625	25%
60	45	15	25%
899	629.30	269.70	30%

Discount vs markup

Discount is measured against the selling price you started from; markup is measured against cost. A shop that marks a 100 item up by 25 percent to 125 and then offers 20 percent off is back at 100, because 20 percent of 125 is 25. The same amount gives different percentages depending on the base.

The profit margin calculator shows margin and markup side by side, so you can see both percentages for the same price.

Common mistakes

• Dividing by the sale price. Discount percentage uses the original price.
• Adding stacked discounts. Multiply the remaining fractions.
• Forgetting tax. Sales tax is usually added after the discount.

A discount is a percentage decrease, so how to decrease a number by a percentage covers the same maths more broadly, including loss percentage.

For grades, see how to calculate percentage of marks.

You can run every one of these percentage checks with a free online calculator from CalculateGuide.