• Minimum: ₩30,000 on a single receipt. Smaller receipts can be aggregated at the airport tax-refund counter on departure, but the in-store instant flow needs the per-receipt floor.
• Passport at checkout. Hand it to the cashier and ask for the tax refund. They scan it; the refund is applied to your total immediately.
• Departure window: leave Korea within 3 months of purchase. The passport scan ties the refund to your trip; staying longer voids it.
• Where it works: the retailer needs to be affiliated with a tax-refund operator. Look for the Global Tax Free / Cube Refund decal at the entrance. Olive Young flagships (Myeongdong, Hongdae, Gangnam, Garosu-gil), department-store cosmetics floors (Shinsegae, Lotte, Hyundai, Galleria), and most brand flagships (Sulwhasoo Bukchon, Tamburins, Hince) are affiliated.
• Duty-free is different. Lotte / Shilla / Incheon duty-free stores sell tax-free at the source: no refund flow because no tax was charged. Goods are picked up at the airport before boarding.
• Higher receipts: single receipts above the per-receipt instant-refund cap (currently ₩600,000 to ₩1,000,000 depending on operator) still earn the refund, but the in-store cap may shift to the airport counter for the overflow. Ask at checkout.

Exact bracket tables are published by Korea's National Tax Service and change periodically. The calculator above uses a 7% midpoint of the typical 6-8% effective range; your real number may differ by ₩1,000-3,000.