Discount Calculator
Find the sale price and how much you save, including stacked discounts.
A percentage from 0 to 100.
Stacking takes the second percent off the already-discounted price.
Final price
- You save
- $20.00
- Effective discount
- 25%
Stacked discounts apply one after another, so the percentages are not simply added.
How the discount calculator works
This tool answers two everyday questions: what does an item cost after a discount, and how much do you save. It also handles the case shoppers get wrong most often, which is stacking two discounts, such as a sale price with an extra coupon on top.
A single discount is straightforward. A percentage p off a price multiplies that price by (1 - p / 100). So 25% off a $80 item is 80 * (1 - 25 / 100) = 80 * 0.75 = $60, and the saving is 80 - 60 = $20.
Stacked discounts apply in sequence, never by addition. Each percentage comes off the price that remains after the previous one. For two discounts that means final = price * (1 - p1 / 100) * (1 - p2 / 100). Because the second discount works on a smaller base, two cuts are always worth a little less than their sum. The calculator keeps full precision through the chain and rounds to the cent only at the end, so the result never drifts by a stray cent. It also reports the effective discount, the single percentage that would give the same final price.
Worked example
A $100 jacket is marked 20% off, and you have a coupon for a further 10%.
- First discount:
100 * (1 - 20 / 100) = 100 * 0.80 = $80 - Second discount, on the new price:
80 * (1 - 10 / 100) = 80 * 0.90 = $72 - You save:
100 - 72 = $28 - Effective discount:
28 / 100 = 28%
| Step | Rate | Price after |
|---|---|---|
| Start | - | $100.00 |
| First discount | 20% | $80.00 |
| Second discount | 10% | $72.00 |
The two discounts feel like 30% off, but they are worth 28%, because the 10% coupon only comes off $80, saving $8 rather than $10. The final price is $72 and you save $28.
How to use it
- Enter the original price before any discount.
- Enter the discount as a percentage, for example 25 for 25% off, not 0.25.
- To model a sale price plus a coupon, turn on Add a stacked discount and enter the second percentage. It is applied after the first, not added to it.
- Read off the final price, the amount you save, and the effective discount that the stack works out to.
- Switch the currency at the top to show the result in your own currency. The math is the same in any currency.
Limitations
This calculator models percentage discounts only. It does not handle fixed-amount coupons such as $10 off, minimum-spend thresholds, buy-one-get-one offers, loyalty points, gift cards, or sales tax, which is normally applied to the discounted price afterward at the till. It assumes every discount applies to the full price of the item. Some real promotions cap the second discount, exclude already-reduced items, or apply tax before the coupon, in which case the order can matter and the final price may differ. Use the result to compare offers and sanity-check a till total, and read the promotion’s terms for the exact rules.
Frequently asked questions
Do stacked discounts add up, so 20% and 10% make 30% off?
No. Stacked discounts apply one after another, each taken off the price that is left after the previous one. A 20% discount on $100 leaves $80, and a further 10% comes off that $80, not off the original $100. The second cut is worth $8 rather than $10, so the combined effect is 28% off, not 30%. Two stacked discounts are always worth slightly less than their sum.
Does the order of two discounts change the final price?
No. Applying 20% then 10% gives the same result as 10% then 20%, because the price is multiplied by both factors and multiplication does not care about order. On $100, both routes land on $72. Order only matters when a discount is capped at a dollar amount or restricted to certain items, which this calculator does not model.
What does the effective discount figure mean?
It is the single percentage that would produce the same final price as the chain of discounts you entered. Two stacked cuts of 20% and 10% give an effective discount of 28%, because $28 saved on a $100 item is 28% of the price. It lets you compare a stacked offer against a single advertised percentage at a glance.
Can a discount be more than 100% or less than zero?
No. A discount above 100% would mean the store pays you to take the item, and a negative discount is really a surcharge. The calculator accepts any percentage from 0 to 100. A 100% discount makes the item free, and a 0% discount leaves the price unchanged.
Is the saved amount the price minus the final price?
Yes. Savings are simply the original price minus the final price, both rounded to the cent so they always reconcile. If the price is $80 and the final price is $60, you save exactly $20, and the final price plus the savings add back to the original price.