Guide type: Avoid mistakes

Stacked Discounts: Why 30% + 20% Off Is Not 50% Off

Sequential percent-off promotions multiply remaining price, they do not add. Learn the correct order, how to compute an effective single discount, and common retail wording traps.

Updated 2026-04-05 • Author: CalcDock Team • Reviewed by: CalcDock Team

This guide is for educational purposes and is not financial, legal, or medical advice.

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Apply discounts in sequence

Take 30% off first: you pay 70% of the tag. Then 20% off the reduced price: you pay 80% of that. Combined you pay 0.7 × 0.8 = 56% of the original — a 44% total discount, not 50%.

Effective single discount

Effective percent off = 1 − (1 − d₁)(1 − d₂) for two discounts d₁, d₂ expressed as decimals.

Coupons and exclusions

Stores may exclude brands or sale items. Read fine print — the mathematical stack only applies to eligible subtotals.

Frequently Asked Questions

Does order matter for two percentage discounts?

For standard successive discounts on the running price, multiplication commutes: 0.7×0.8 = 0.8×0.7.

What if tax is applied?

Tax jurisdiction rules vary; some apply tax before coupon, some after. Your receipt is authoritative.

Related Calculators

Discount Calculator Percentage Calculator VAT Calculator

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Sources & References

Khan Academy — Successive discounts (concept)

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