Reckonary / Everyday / Stacked discounts
Why 20% off then 10% off isn't 30% off
An extra 10% off an already 20%-off tag feels like 30% off. It isn't — you save 28%, and that same multiply-don't-add trick sits behind every "stack these coupons" sign.
So how much is 20% off then 10% off?
Take 20% off, then 10% off what's left, and you've saved 28% of the original price — not 30%. The second discount is smaller than it looks because it only applies to the already-reduced price, not the full one.
Walk it through with $100
Start with a $100 jacket. The first 20% off drops it to $80. The next 10% comes off that $80, not the original $100 — so it's $8, not $10, and you land at $72. You saved $28 in all, which is 28% of where you started. A straight 30% off would have taken it to $70.
Drag two discounts on a $100 item and watch the real total:
Why the percentages don't add up
The second discount can only work on the money the first one left behind. After 20% off, just 80% of the price is still there, so the 10% cut is really 10% of that 80% — eight cents on the original dollar, not ten. That missing slice is why stacked discounts always land below the sum. And the bigger the discounts, the wider the gap: 50% plus another 50% isn't 100% off — you'd never pay nothing — it's 75%.
What common stacked discounts really save
| Discounts | Sounds like | Actually |
|---|---|---|
| 20% + 10% | 30% | 28% |
| 25% + 15% | 40% | 36.25% |
| 30% + 20% | 50% | 44% |
| 40% + 10% | 50% | 46% |
| 50% + 20% | 70% | 60% |
| 50% + 50% | 100% | 75% |
Does the order change anything?
Not for two percentages. Twenty percent then ten, or ten percent then twenty — both land at 28%, because you're multiplying the same two numbers either way. Order only starts to matter when a flat dollar coupon joins in: $10 off then 20% off leaves you at $72, while 20% off then $10 off lands at $70, because the percentage and the fixed amount bite in a different sequence.
Check any combination against the sticker price:
Open the stacked discount calculator →Percentages fool people in the other direction too. If you sell things rather than buy them, see Markup vs margin — why a 50% markup is only a 33% margin. The other shelf trap works on sizes instead of percentages: the bulk size is cheaper until you throw enough away.
Frequently asked questions
Does the order of the discounts matter?
Not when both are percentages. Twenty percent then ten percent gives the same 28% as ten percent then twenty, because you are multiplying the same two numbers either way. The one exception is a flat dollar coupon: mixing $10 off with a percentage does depend on which comes first, so take the percentage off before the dollar coupon when you can choose.
What is the quick formula?
Multiply what is left after each cut. For 20% then 10%, that is price times 0.80 times 0.90. To get the true discount in one step, do 1 minus (0.80 times 0.90), which is 28%.
Is a single 30% off better than 20% plus 10%?
Yes. A straight 30% takes $30 off a $100 item; the stacked pair takes $28. One larger discount always beats two smaller ones that appear to add up to the same number.
Do stores stack discounts on purpose?
Often. 'An extra 10% off already-reduced prices' sounds bigger than the handful of points it really adds — layered onto a 20%-off tag, a 10% coupon is worth about 8 more points, not 10. Knowing the real number keeps the sign from doing your math for you.
Last reviewed July 2026. This guide is for education, not financial advice.