About this tool
A credit card installment fee calculator (카드 할부 수수료 계산기, card installment interest calculator) shows how much extra you pay when you split a purchase into months with a Korean credit card.
Interest-bearing installments are usually charged on the remaining balance each month at the card company's yearly fee rate, with the same principal paid each month.
This tool uses that equal-principal approach: monthly principal = amount / months; fee in a month = remaining balance x yearly rate / 12; total fee = amount x rate / 12 x (months + 1) / 2.
The yearly rate depends on your card company, your credit grade and the number of months, so type the rate printed on your card terms or app.
Interest-free installments are offered by many cards on selected months, in which case the fee is zero. How much is the fee for a 3,000,000 won purchase over 12 months at 15% a year?
Total fee = 3,000,000 x 15% / 12 x 13 / 2 = 243,750 won, the first month is 287,500 won, the last month 253,125 won and the total payment 3,243,750 won. What about 1,200,000 won over 6 months at 15.9%?
Total fee about 55,650 won. Is a longer installment cheaper per month but costlier overall? Yes, each added month adds more fee, so a short period or interest-free option is cheaper overall.
Real card statements calculate by days and may round differently, so treat this as a reference result that does not replace the terms of your card company or a financial professional.
How to use
- Enter the purchase amount in won.
- Enter the number of installment months and the yearly fee rate from your card terms.
- Read the total fee, the first and last monthly payments and the total cost.