Multi-Tier Discount StackingMerchant Margin CheckSales Tax Included

Discount Calculator: Sale Price, Savings & Stacked Coupons

Calculate the final price and total savings from an original price and a discount — stack a second coupon, add sales tax, and (for sellers) see how the markdown affects gross margin.

Promotion Parameters

Single or stacked sequential discounts

Before any discount
$
Presets:
%
Stacked Coupon / Extra MarkdownSequential

Applied to the already-discounted price (e.g. VIP code on a sale item). Set to 0 for none.

%
%
Sellers, optional
$
Discount VerdictEffective reduction from the original price
—
Final Price (Out the Door)
—
Sale price before tax: ——

You Save

—
—

Original Price

—
Before discounts and tax
Stacking Audit
—
Seller Margin Check—
Gross margin at full price—
Gross margin after discount—
Gross profit given up per unit—

Discount Sensitivity Matrix

Customer price and savings at common discounts — and, for sellers, the extra unit sales needed to keep gross profit dollars the same.

—
Promotion ScenarioEffective DiscountPre-Tax PriceCustomer SavingsGross Profit / UnitUnit MarginVolume Needed to Break Even
*Volume needed = (full-price gross profit ÷ discounted gross profit) − 1, assuming a constant cost per unit. "Loss" means the price is below cost.

Why 20% + 20% Is Not 40% Off

Checkout systems apply a second discount to the already-reduced price, so stacked percentages multiply rather than add:

Final factor = (1 − D₁) × (1 − D₂) = 0.80 × 0.80 = 0.64 → a 36% effective discount, not 40%.

The bigger the discounts, the bigger the gap between the "added" and the real figure.

Volume vs Margin: How Many Extra Units to Break Even?

Sellers often underestimate how many extra units a markdown needs. For a product with a 40% gross margin, a 20% discount halves the gross profit per unit.

Extra volume = D ÷ (M − D) = 0.20 ÷ (0.40 − 0.20) = +100% — twice the units just to earn the same gross profit.

How stacked discounts work

Apply discounts one after another, not by adding the percentages. 30% off then 10% off is 37% off, not 40%.

Example: a $150 jacket at 35% off is $97.50. A further 10% coupon on $97.50 saves $9.75, for a final price of $87.75.

More examples: discount calculator guide. To add sales tax on its own, use the Sales Tax Calculator.

By Suhaib Hassan · Formula verified 27 Sep 2026 · How CalculatePilot verifies formulas →

Frequently asked questions

How do I stack two discounts?

Apply them sequentially. 20% then 10% off is 28% off, not 30%.

How do I get the original price from a sale price?

Divide the sale price by (1 minus the discount as a decimal). $60 at 25% off was $80.

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