Guides/Successive discounts
Successive discounts vs one combined percent
Stacking “20% off, then another 10% off” feels like 30% off. Math disagrees: each percent applies to what is left, so the combined savings are less than the sum of the labels.
Multiply what remains
- After 20% off you pay 80% (factor 0.80).
- Then 10% off that: pay 90% of the already-reduced price (factor 0.90).
- Combined pay factor = 0.80 × 0.90 = 0.72 → you pay 72%, i.e. 28% off, not 30%.
Worked dollar example
- Item $100 → 20% off → $80.
- 10% off $80 → $8 more off → $72.
- True single equivalent discount: (100 − 72) / 100 = 28%.
- A true 30% off would be $70 — two dollars cheaper than the stack.
Order of discounts
For pure percentage stacks on one price, order does not change the final factor (multiplication is commutative). Order does matter when a fixed-dollar coupon mixes with percents, or when one discount excludes sale items.
Related percent topics
Discount math·Compound % increase·Original before discount·Reverse percentage
Common mistakes
- Adding 20 + 10 = 30 and calling that the stack.
- Applying both percents to the original instead of sequentially.
- Confusing “% off” with “% of” wording —percent off vs of.