Discount Calculator
Calculate sales discounts, sale prices, and compounded sequential promotional savings.
Last verified: September 2026Inputs & Parameters
Calculation Results
Sequential stack of 20% + 10% equals 28.00% effective discount (not 30.00%).
Calculating Promotional Discounts and Stacked Savings
Discount calculations determine final consumer prices, markdown amounts, and optional downstream sales tax charges. Retailers and shoppers frequently encounter stacked discounts (such as a 20% sale combined with an extra 10% loyalty coupon), which apply sequentially rather than additively.
Core Mathematical Formulas
- Single Discount:
Sale Price = Original Price × (1 - Discount% / 100) - Sequential Stacked Discounts:
Price_final = Original × (1 - D1%) × (1 - D2%) - Effective Combined Discount %:
Effective Discount = [1 - (1 - D1%) × (1 - D2%)] × 100 - Total Savings:
Savings = Original Price - Price_final
Worked Example
An item priced at $100.00 receives a 20% primary discount plus an additional 10% stacked coupon:
1. After First Discount (20%) = $100.00 × 0.80 = $80.00
2. After Second Discount (10% of $80) = $80.00 × 0.90 = $72.00
3. Total Savings = $100.00 - $72.00 = $28.00
4. Effective Combined Discount = 28.00% (compounded sequentially, not 30.00%)
Assumptions & Limitations
Stacked discounts apply sequentially to the remaining balance, not additively (20% + 10% yields 28% total discount, not 30%). Any post-discount sales taxes should be evaluated separately using dedicated jurisdiction tax rates.