クーポン計算機

計算原理と数学公式

Coupon Calculation Logic:

1. Member Discount Calculation:
   Member discount amount = Original price × Member discount percentage ÷ 100
   Price after member discount = Original price - Member discount amount

2. Coupon Application Conditions:
   Only when the price after member discount ≥ Coupon minimum amount, the coupon is applied

3. Coupon Type Calculation:
   - Discount Coupon: Discount amount = Price after member discount × Discount percentage ÷ 100
   - Amount Off Coupon: Discount amount = Coupon value
   - Free Shipping Coupon: Discount amount = Shipping fee
   - Cash Back Coupon: Discount amount = Coupon value

4. Final Price Calculation:
   Final item price = Price after member discount - Coupon 1 amount - Coupon 2 amount
   Total payment amount = Final item price

5. Savings Calculation:
   Total savings = Original price - Total payment amount