We calculated how much a 2.7% card fee actually costs over a year
2025-12-08
Percentages alone don't give you a real sense of fees. Let's calculate the actual amounts based on a solo business owner billing 5 million KRW per month.
Annual billing of 60 million KRW, all paid by card. Under a 2.7% structure, 1.62 million KRW goes to fees. If a flat per-transaction fee is added on top (2.9% + 300 KRW per transaction), based on 10 transactions a month, that becomes 1.74 million KRW + 36,000 KRW = 1.776 million KRW. The difference is about 150,000 KRW. Up to this point, it doesn't look like much.
Add a subscription fee, and the story changes. If you're on a 50,000 KRW/month plan, that's another 600,000 KRW a year, straight on top. Combined with the 150,000 KRW difference in payment fees, that's 750,000 KRW a year. If your billing amount doubles, the fee difference doubles too, but the subscription fee stays the same — so the smaller your billing amount, the more brutal the subscription fee's share becomes.
Switch to bank transfer, and the gap widens. Receiving that same 60 million KRW via a 1% bank transfer costs 600,000 KRW. That leaves 1.02 million KRW more than the card option. In practice, clients choose their own payment method, so you can't route everything through bank transfer — but simply displaying bank transfer as the default option for larger invoices shifts the balance.
There are two items commonly left out of these calculations. First, withdrawal fees. Many platforms charge a per-transaction fee when moving your balance to your own bank account. Second, the currency conversion spread. If you have overseas clients, the gap between the quoted exchange rate and the applied rate typically runs around 1%, which means your actual take-home is lower than the surface-level fee suggests.
Bottom line. Don't just compare percentages — calculate (annual billing amount × fee rate) + (subscription fee × 12) + (withdrawal and conversion costs) in one line. For most solo business owners, this total ends up being roughly the size of a month's revenue.