How stacked discounts really work
When two discounts apply one after another, they do not simply add up. The second discount comes off the already-reduced price, so the combined saving is less than the sum of the two. This calculator shows the final price and the true effective discount when you stack two offers.
Worked example
A 100 item with 20% off, then a further 10% off: the first cut gives 80, then 10% off 80 gives 72. You pay 72, an effective discount of 28%, not 30%.
Why it matters
"20% off plus an extra 10%" sounds like 30%, but it is really 28%. Knowing the true figure helps you compare a stacked offer against a single bigger discount.
Frequently asked questions
Do two discounts add together?
No. The second applies to the reduced price, so 20% then 10% is 28% off, not 30%. Stacked discounts are always a little less than the sum.
Is a single 30% better than 20% plus 10%?
Yes. A single 30% off beats stacking 20% and 10%, which only comes to 28%. Always compare the effective rate.
Does the order of discounts matter?
No. Multiplying two percentage discounts gives the same result in either order, so 20% then 10% equals 10% then 20%.
How do I add three discounts?
Run the result through the calculator again as the original price with the third discount.
Is a tax added before or after?
That depends on the store. Use the VAT calculator on the final price if tax is added at the till.