🏷️ Shopping & Retail Finance
Discount & Sales Tax Calculator
Calculate final out-of-pocket costs, stacked coupon savings, and sales tax in real-time.
Common Sales:
20% Off Sale
30% Off + 10% Extra Coupon
50% Half Price
Black Friday (40% + 20% Stack)
Final Price After Discounts & Tax
$72.90
Cost Breakdown:
Original Price
$100.00
Total Savings
$32.50
Sales Tax Amount
$5.40
Effective Discount
32.5%
How Stacked Retail Discounts Work
When retailers offer a storewide sale (e.g. "30% Off") plus an additional checkout coupon (e.g. "Take an extra 20% Off with code SAVE20"), the discounts are applied sequentially rather than added together:
Final Pre-Tax Price = Original × (1 − Discount 1) × (1 − Discount 2)
Example: $100 × (1 − 0.30) × (1 − 0.20) = $100 × 0.70 × 0.80 = $56.00 (a 44% total discount, not 50%).
Frequently Asked Questions
In almost all jurisdictions, sales tax is calculated on the discounted purchase price (the actual amount paid at the register) rather than the original manufacturer suggested retail price (MSRP).