Double Discount Calculator
Stack two discounts and see the true combined percentage off.
About the Double Discount Calculator
Enter the original price and the two discounts, for example a sale price plus an extra coupon. The calculator gives the final price, the combined discount and how much you save.
When a shop offers an extra discount on sale prices, the second percentage comes off the already-reduced price, not the original. So 30% + 20% is 44% off, not 50%.
The formula
Combined = 1 − (1 − d₁)(1 − d₂)
- d₁, d₂
- the two discounts as decimals (30% = 0.30)
Worked example
A 120 jacket, 30% off, then an extra 20% at the till
- After 30%: 120 × 0.70 = 84
- After another 20%: 84 × 0.80 = 67.20
- Total saving 52.80, which is 44% off
Things to keep in mind
- Sales tax or VAT added afterwards is not included.
Questions people ask
Does the order matter?
No. 20% then 30% gives the same result as 30% then 20%.
What about three discounts?
Multiply all the (1 − d) factors together: 30%, 20% and 10% gives 1 − 0.7 × 0.8 × 0.9 = 49.6% off.
Is “buy one get one half price” a 25% discount?
Yes, on two equal items: you pay 1.5 prices for 2, which is 25% off each.