How it is calculated
- Sale price = original price × (1 − discount rate)
- Discount rate = (original price − sale price) ÷ original price × 100
- Original price = sale price ÷ (1 − discount rate)
- Stacked discounts multiply rather than add. 20% then 10% is 0.8 × 0.9 = 0.72, a real discount of 28%
| Discounts | Simple sum | real discount rate |
|---|---|---|
| 10% + 10% | 20% | 19% |
| 20% + 10% | 30% | 28% |
| 30% + 20% | 50% | 44% |
| 50% + 10% | 60% | 55% |
For sellers: discounts come straight out of profit
At a 30,000 KRW price with 18,000 KRW of cost and shipping and a 6% fee, profit per unit is about 10,200 KRW. Take 20% off and the price is 24,000 KRW, with profit of about 4,560 KRW, more than halved . Profit falls much faster than the discount rate. Before a promotion, enter your cost in step 4 to check.
FAQ
How is a discount rate calculated?
(Original price − sale price) ÷ original price × 100. A 50,000 KRW item sold for 39,000 KRW is 11,000 ÷ 50,000 = 22% off.
Is 10% plus another 10% off equal to 20%?
No. The second discount applies to the already discounted price, so 0.9 × 0.9 = 0.81: a real discount of 19%.
Can I work back to the original price?
Use sale price ÷ (1 − discount rate). If 30% off gives 35,000 KRW, the original price is 50,000 KRW. Choose "Original price" above.
Do coupons affect marketplace fees?
Both Smart Store and Coupang charge fees on what the customer actually paid, so a seller coupon that lowers the payment lowers the fee too. This calculator’s margin also uses the discounted amount.
Related: Coupang sales fees explained · Naver Smart Store fees explained