How to Calculate Discounts, Stacked Coupons & Sales Tax
Whether you are shopping online, browsing retail department store markdowns, or analyzing promotional marketing materials for your business, knowing how to calculate discount percentages is a highly practical skill.
Standard Percentage Discount Formula
Calculating a single percentage discount is straightforward. You find the savings amount by multiplying the original price by the discount percentage, then subtract that amount from the original price:
Savings = Original Price × (Discount % ÷ 100)
Final Sale Price = Original Price - Savings
For example, if an item costs $50.00 and is on sale for 20% off:
Savings = $50.00 × 0.20 = $10.00Sale Price = $50.00 - $10.00 = $40.00
The Math of Double & Stacked Discounts
Retailers often run promotions like "Take an additional 20% off already reduced clearance items." Many shoppers mistakenly add these percentages together (e.g. 20% off plus 10% off equals 30% off).
However, the second discount is applied sequentially to the *already reduced price*:
- If a $100 item is discounted 20%, the price drops to $80.
- The second 10% discount is calculated on $80 (saving $8), bringing the final price to $72.
- Your total net discount is 28%, not 30%.
Use our calculator to stack multiple coupons, deduct flat cash-off amounts, and add local state sales tax to verify your exact checkout total.
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