Discount calculator
Calculate the final price and savings of a discount, including a second successive discount and the combined effective percentage.
What this calculator does
This calculator finds the final price and the savings of a discounted product from the original price and the discount percentage.
It also lets you chain a second successive discount (for example, a seasonal sale plus a coupon) and shows the combined effective discount, which is always smaller than the sum of both percentages.
The result updates instantly as you type, with a breakdown of each step of the calculation.
Who it is for
- Shoppers who want to know what they will pay and how much they save before checkout.
- Shop owners setting markdowns who need the exact final price the customer will see.
- Anyone combining promotions (sale + coupon) who wants to know the real total discount.
- Students learning why successive discounts do not simply add up.
What information you need
- The original price of the product, before any markdown.
- The main discount percentage, for example 20.
- Optionally, the percentage of a second discount applied on the already-reduced price.
How it is calculated
The discount is the price multiplied by the percentage and divided by 100; the final price is the original price minus that discount.
If there is a second discount, it applies to the already-reduced price, not to the original. That is why 20% and 10% discounts are not a 30% discount, but an effective 28%.
The combined effective discount uses the formula d1 + d2 − (d1 × d2) ÷ 100, which expresses the total savings as a percentage of the original price.
Each discount is rounded to 2 decimal places (half up) on its own line; the original price minus the total saved always equals the final price exactly.
Formula
- Single discount
final price = price − (price × discount ÷ 100)- Second successive discount
final price = reduced price − (reduced price × second discount ÷ 100)- Combined effective discount
effective % = d1 + d2 − (d1 × d2) ÷ 100
Worked example
An $80 jacket has a 25% discount and you pay with an additional 10% coupon. What do you pay, and what is the real discount?
- First discount: $80 × 25 ÷ 100 = $20. The price drops to $80 − $20 = $60.
- Second discount on the reduced price: $60 × 10 ÷ 100 = $6. The price drops to $60 − $6 = $54.
- Total saved: $20 + $6 = $26. Effective discount: 25 + 10 − (25 × 10) ÷ 100 = 32.5%.
You pay $54.00, you save $26.00, and the effective discount is 32.5% — not 35%.
How to interpret the result
The total saved is in the same currency as the price; the effective discount expresses it as a percentage of the original price.
The effective discount is always smaller than the sum of the two percentages: the second discount acts on a smaller base.
Check how the promotion is stated: mathematically, the order of two percentage discounts does not change the final price (25% then 10% costs the same as 10% then 25%).
Common mistakes
- Adding the percentages of successive discounts: 20% + 10% is not 30%, it is an effective 28%.
- Applying the second discount to the original price instead of the already-reduced one.
- Confusing the money saved with the percentage: a large discount on a small price can save less than a small discount on a large price.
- Assuming a 50% discount followed by another 50% makes the product free: it ends at 25% of the original price.
Frequently asked questions
Why is 20% plus 10% not 30%?
Because the second discount is calculated on the already-reduced price. With $100: 20% leaves the price at $80, and 10% of $80 is $8, not $10. The total saved is $28 — an effective 28%.
Does the order of the discounts matter?
Not for the final price: multiplying by 0.80 and then 0.90 gives the same as multiplying by 0.90 and then 0.80. The intermediate breakdown changes, but the result is identical.
How do I find the original price from the reduced price?
Divide the reduced price by (1 − discount ÷ 100). For example, if you paid $54 with a 10% discount, the previous price was 54 ÷ 0.90 = $60.
Can I use a 100% discount?
Yes: a 100% discount leaves the final price at zero (a free product). Values above 100 are rejected because they would produce a negative price.
Sources
- Last reviewed:
- July 21, 2026
- Calculation version:
- 1.0.0
Important notice
The results of these calculators are informative estimates and may differ from official calculations. They do not constitute legal, tax, or financial advice. Always verify with the competent institutions or a professional.