Sale price after a discount
- $80.00 × (1 − 20 ÷ 100) = $64.00
Discount percentage from two prices
- ($80.00 − $56.00) ÷ $80.00 × 100 = 30%
Stacked discounts (e.g. 20% then 10%)
- $120.00 × (1 − 20 ÷ 100) = $96.00
- $96.00 × (1 − 10 ÷ 100) = $86.40
- $33.60 ÷ $120.00 × 100 = 28% total discount
How to use
- To find a sale price, enter the original price and the discount percentage.
- To find how big a discount is, enter the original price and the price you will pay.
- For stacked offers, such as 20% off plus an extra 10% at checkout, enter each discount in order.
- Check the formula under each result to see how the price was worked out.
Know what you are really paying
Shops present discounts in many ways: a percentage off, a before-and-after price, or several offers combined at checkout. Comparing them in your head is error-prone, especially when discounts stack. This calculator covers the three most common situations and shows the arithmetic, so you can check a receipt or compare two offers with confidence.
Formulas
- Sale price = original price × (1 − discount ÷ 100)
- Amount saved = original price − sale price
- Discount percentage = (original price − sale price) ÷ original price × 100
- Stacked discounts: apply each discount to the result of the previous one. The total discount is 1 − (1 − d₁) × (1 − d₂) × …
Stacked discounts explained
Suppose a jacket costs $120. The store takes 20% off, and a coupon gives an extra 10% at checkout. After the first discount the price is 120 × 0.8 = $96. The coupon then applies to $96, not $120: 96 × 0.9 = $86.40. You save $33.60, which is 28% of the original price. Many shoppers expect 30%, which would be $84, so the difference adds up quickly on larger purchases.
A useful rule of thumb: two stacked discounts always give less than their sum, and the gap grows as the discounts get bigger. 50% plus 50% is 75% off, not free.
Comparing offers
Is “30% off” better than “20% off plus 10% extra”? Yes: 30% off beats 28% off. Is “buy two, get the second at half price” better than 20% off each? Two items at half price for the second works out to 25% off the pair, so it wins if you really need both. Convert each offer into a single percentage or a final price and the choice becomes obvious.
Rounding
Prices are rounded to the nearest cent for display, while the calculation keeps full precision. Stores may round each step separately, so a receipt can differ by a cent from the result here. That is normal and does not mean the discount was applied incorrectly.
Frequently asked questions
- How do I calculate a sale price?
- Multiply the original price by one minus the discount rate. For $80 with 20% off, that is 80 × (1 − 0.20) = $64. The amount you save is 80 − 64 = $16.
- How do I calculate the discount percentage?
- Subtract the sale price from the original price, divide by the original price and multiply by 100. An $80 item on sale for $56 is (80 − 56) ÷ 80 × 100 = 30% off.
- Is 20% off plus an extra 10% off the same as 30% off?
- No. The extra 10% applies to the already reduced price, so the total discount is 28%, not 30%. On a $100 item you pay $72 instead of $70.
- Does the order of stacked discounts matter?
- For percentage discounts, no. Multiplication gives the same result in any order. It does matter when a fixed amount off is combined with a percentage, which this calculator does not cover.
- Why is the discount negative?
- If the price you entered is higher than the original, the change is a price increase, which is shown as a negative discount.
- Does the calculator include sales tax?
- No. Sales tax is added after discounts and varies by location. Use the percentage calculator to add tax to the final price.