Why is stacking 20% then 10% not 30% off?

Each discount applies to the already-reduced price, not the original. 20% off 100 leaves 80, then 10% off 80 leaves 72 — a 28% effective saving, not 30%. Stacked discounts always compound to less than the sum of the percentages.

Does the order of discounts matter?

For percentage-only discounts the final price is the same whatever order you apply them, because multiplication is commutative. Order only matters when fixed-amount vouchers are mixed in, which this tool does not model.

Completely. All calculations run locally in your browser using JavaScript. No prices or percentages are sent to any server, stored or logged.

Discount Stacking Calculator

Discount stacking calculator

Combine two or more discounts on a single price and see the true compounded saving. Because each discount applies to the already-reduced price, stacked discounts always save less than the sum of the percentages.

For example, 20% off then 10% off gives a 28% effective discount, not 30%. The calculator shows the final price, the amount saved, the effective percentage off, and a clear step-by-step breakdown.

Everything runs in your browser — nothing is uploaded or stored.