Stacked Discount Calculator
Free stacked discount calculator. Apply up to three sequential discounts to a price and see the true final total and combined percentage off.
A stacked discount calculator applies up to three discounts one after another and shows the real final price and the true total percentage off. Stacking is not additive: 20% off followed by 10% off a $200 item leaves $144, a 28% total reduction rather than 30%.
How stacking works
Each discount is applied to the price that remains after the previous one, never to the original list price. With the three discount percentages written as d1, d2, and d3:
final = price × (1 − d1 ÷ 100) × (1 − d2 ÷ 100) × (1 − d3 ÷ 100)
Any discount left at zero is skipped, so you can use the tool for one, two, or three stacked offers. Total saved = price − final, and the combined percentage = saved ÷ price × 100.
Worked example with the defaults
| Step | Calculation | Result |
|---|---|---|
| After first discount | $200 × (1 − 0.20) | $160.00 |
| After second discount | $160 × (1 − 0.10) | $144.00 |
| Third discount (0%) | unchanged | $144.00 |
| Amount saved | $200 − $144 | $56.00 |
| Combined discount | $56 ÷ $200 × 100 | 28.0% |
The two percentages sum to 30%, but the second discount only applies to $160, not $200, so $4 of the nominal 30% never materialises.
Effective totals for common stacks
| Stack | Effective total off | Final price on $100 |
|---|---|---|
| 10% + 10% | 19% | $81.00 |
| 20% + 10% | 28% | $72.00 |
| 25% + 20% | 40% | $60.00 |
| 30% + 20% | 44% | $56.00 |
| 30% + 30% | 51% | $49.00 |
| 50% + 50% | 75% | $25.00 |
| 20% + 10% + 5% | 31.6% | $68.40 |
Every added discount has less effect than the one before it, which is why a “second 50% off” never produces a free item.
Common mistakes
- Adding the percentages. 20% + 10% is 28% off, not 30%. The difference grows as the discounts get larger.
- Assuming codes stack. Many retailers allow only one promo code per order; the calculator cannot tell you whether a specific store permits it.
- Forgetting tax and shipping. Sales tax is charged on the discounted subtotal, and shipping is usually not discounted at all.
- Applying the second discount to the list price. It always applies to the already-reduced total.
Why is a 50% plus 50% discount only 75% off?
The second 50% applies to the half that remains, removing a quarter of the original price. The two halves never overlap, so a free item is impossible through percentage stacking alone.
Can I use this for a sale plus a coupon?
Yes — enter the sale percentage as the first discount and the coupon as the second. Just check the retailer’s rules, since some coupons apply only to full-price items.
Does the order of discounts matter?
No. Multiplication is commutative, so 20% then 10% gives the same final price as 10% then 20%. What matters is the size of the discounts, not their sequence.
How to use the result
- Compare the combined percentage with the sum of the individual discounts to see how much the stack gives up.
- Apply tax after the discounts, not before; the discounted subtotal is what gets taxed.
- Check the store’s terms, since the final price assumes every discount is allowed to stack.
How do I stack three discounts correctly?
Enter the first two in the first and second fields and the third in the member/promo field. The order does not change the result, but each must be applied to the running total rather than the original price. Leaving a field at zero simply omits that step. If a promo is a flat dollar amount rather than a percentage, subtract it from the price yourself after running the percentages here.
Is a stack of 20% and 10% the same as 30% off?
No. It equals 28% off. The gap is small at modest discounts but widens quickly: 30% plus 30% is 51%, not 60%, and 50% plus 50% is 75%, not 100%. A fixed-dollar coupon behaves differently again, because it is subtracted after the percentages rather than multiplied through them.
Stacked discounting is the mirror image of the markup calculator, which prices an item up from cost. Once you have the discounted subtotal, the sales tax calculator adds the applicable tax.