Discount percentage calculator

What is a discount percentage calculator?

A discount percentage calculator works backwards from two prices you already know: the original (pre-sale) price and the discounted sale price. Instead of telling you the final price, it answers a different question — “how big is this discount?” You enter both prices and the tool returns the percentage off along with the amount of money you save.

This is handy when a store advertises a sale price without telling you the percentage, or when you want to compare two offers that are quoted in different ways. Knowing the true percentage off lets you judge at a glance whether a deal is genuinely generous or only modest.

How to use this calculator

Enter the original price of the item in the first field and the sale price in the second field. The calculator instantly shows the discount as a percentage and the amount saved in money. Both prices must be greater than zero for the percentage to be meaningful.

Formula

The discount percentage is the difference between the two prices divided by the original price, expressed as a percentage:

$\text{discount \%} = \frac{P_{orig} - P_{sale}}{P_{orig}} \times 100$

The amount saved is simply the difference between the two prices:

$\text{amount saved} = P_{orig} - P_{sale}$

Example

An item originally priced at $80 is on sale for $60. The discount percentage is:

$\frac{80 - 60}{80} \times 100 = \frac{20}{80} \times 100 = 25\%$

So the item is 25% off, and you save $20.

Examples

1. Original price: $200, sale price: $150.

   $\frac{200 - 150}{200} \times 100 = 25\% \quad\text{saved } \$50$

2. Original price: $100, sale price: $75.

   $\frac{100 - 75}{100} \times 100 = 25\% \quad\text{saved } \$25$

Notes

The percentage is always measured against the original price, not the sale price — this is why a $20 saving on an $80 item is 25%, not 33%. If the sale price is higher than the original price, the result becomes negative, which signals a price increase rather than a discount.

FAQs

How do I find the percentage off from two prices?

Subtract the sale price from the original price, divide that difference by the original price, and multiply by 100. This calculator performs the steps for you the moment you enter both values.

Why is the percentage based on the original price?

Discounts describe how much of the original price you no longer pay. Dividing by the original price keeps the figure consistent with how retailers advertise sales, so a “25% off” tag always refers to a quarter of the starting price.

What does a negative discount percentage mean?

A negative result means the sale price is higher than the original price, so the item has gone up in cost rather than down. Double-check the two values you entered if you see a negative number.

Is the amount saved the same as the discount percentage?

No. The amount saved is the money difference between the two prices, while the discount percentage expresses that saving relative to the original price. The same dollar saving can represent very different percentages depending on the starting price.

You can also explore the related discount calculator, markup calculator, and margin calculator.