Installment Fee Calculator
See exactly how much a credit card installment plan costs, broken down by installment. Calculates total fee, total payment and monthly payment on a declining-balance equal-principal basis, with a side-by-side interest-free comparison.
Enter Installment Details
Market range: 5.5%–19.9% annually. Default 15.0% is illustrative (2026-07-26).
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Installment Fee
Monthly basis · Card issuers use daily basis- Installment Principal
- 1,200,000KRW
- Total Fee Annual Installment Fee Rate 15.0%
- 97,500KRW
- Total Payment
- 1,297,500KRW
- 1st Installment
- 115,000KRW
An interest-free 12-month plan totals 1,200,000 KRW—97,500 KRW less than your current terms. Check for interest-free promotions first.
Lowering the rate by 1%pp to 14.0% annually saves 6,500 KRW.
For larger amounts over a longer term, Loan Interest Calculator to compare with personal loan terms.
머니플(Moneyple)의 할부 수수료 계산기는 회차별 잔액 기준 이자와 무이자 할부 차액을 비교한다.
What This Number Means
할부 수수료는 남은 잔액에 월 이자율을 곱해 매달 부과된다. 무이자 할부와 비교하면 유이자 할부의 실제 추가 비용을 알 수 있다.
3 Common Mistakes People Make Here
- 할부 수수료가 총 금액에 한 번만 붙는다고 생각한다 — 매달 잔액에 이자가 붙으므로 회차별로 다르다.
- 무이자 할부에 숨은 비용이 없다고 생각한다 — 무이자 할부는 가맹점이 수수료를 부담하는 구조다.
- 할부 수수료율을 연이율과 혼동한다 — 할부 수수료는 명목금리이며 실질금리와 다를 수 있다.
120만원을 연 15% 12개월 할부로 사면 수수료 합계가 붙는다 — 무이자 할부와 비교하면 실제 차액을 확인할 수 있다.
머니플(Moneyple) · Formulas and rates verified by humans; commentary drafted with AI assistance and reviewed by the operator
How is the installment fee calculated?
Each month, the monthly fee rate is applied to the remaining balance. The principal is divided equally across the months, and as the balance declines, the fee shrinks too. The first installment carries the highest fee and the last the lowest. This is structurally identical to an equal-principal amortization loan.
Monthly principal = installment principal / number of months n
Fee for installment k = remaining balance x (annual rate / 12)
Total fee = principal x (annual rate / 12) x (n + 1) / 2
Worked example — A 1.2 million KRW purchase on a 12-month plan at 15% annually has a monthly principal of 100,000 KRW and a monthly fee rate of 15% / 12 = 1.25%. The 1st installment fee is 1,200,000 x 1.25% = 15,000 KRW; the 12th is just 100,000 x 1.25% = 1,250 KRW. The total fee is 97,500 KRW and total payment is 1,297,500 KRW. Closed-form check: 1,200,000 x 1.25% x (12 + 1) / 2 = 97,500 KRW. A 600,000 KRW purchase on 3 months at 10% gives a total fee of just 10,000 KRW (total 610,000 KRW).
Watch out — More months lowers the monthly burden but raises the total fee, which scales roughly with (n + 1) / 2. Rates also vary by card issuer, plan length and credit score. A 3 million KRW purchase on 12 months at the market-high 19.9% pushes the total fee to 323,375 KRW. Conversely, cutting the rate by just 1%pp saves 6,500 KRW on a 1.2M / 12-month plan. Checking for interest-free promotions first is the surest saving.
Why does my card issuer's bill differ by a few thousand KRW?
Card issuers calculate on a daily basis, not monthly. Their actual formula is "remaining balance x annual rate x usage days / 365." Usage days are the calendar days between the card-acquisition date and the billing date, varying from installment to installment depending on when you swiped and what your billing date is.
- This calculator's approach — Usage days are unknowable at purchase time, so we default to monthly accrual (annual rate / 12) and disclose the difference. Guessing at daily accrual with arbitrary assumptions would be less accurate, not more.
- Size of the difference — Typically a few thousand KRW in total. The gap widens when the first installment's usage days diverge significantly from 30.
- The default rate 15.0% is illustrative (as of 2026-07-26). Look up your actual rate on the Credit Finance Association's disclosure portal or your card issuer's app. The market range is 5.5%–19.9% annually.
Per-installment fees are rounded to the nearest KRW, so summing the rows may differ from the total by a few KRW. This calculator computes the total from exact pre-rounding values and notes any discrepancy below the table, rather than silently adjusting any single installment.
Frequently Asked Questions
Q. How is the credit card installment fee calculated?
Each installment's fee equals the remaining balance times the monthly fee rate (annual rate / 12). The principal is repaid in equal monthly amounts, so the balance — and therefore the fee — shrinks each month. For example, 1.2 million KRW on 12 months at 15% annually: the 1st fee is 1.2M x 1.25% = 15,000 KRW, but the 12th is only 1,250 KRW on a 100K balance. Total fee: 97,500 KRW, total payment: 1,297,500 KRW.
Q. How much interest does a 12-month plan add?
It scales with principal and rate. At 15% annually, the total fee on a 12-month plan is about 8.1% of the principal — 97,500 KRW on 1.2 million. At the market-high 19.9% on 3 million KRW, the total fee climbs to 323,375 KRW, making the total payment 3,323,375 KRW.
Q. Is interest-free installment really free?
The consumer pays zero fees, yes. The cost is absorbed by the card issuer and the merchant (or manufacturer/distributor), which may be reflected in product pricing or reduced rewards.
Q. How do I find my installment fee rate?
Check your card issuer's app or website under product disclosures, or the Credit Finance Association's public disclosure portal for rate ranges by card and plan length. The market range is roughly 5.5%–19.9% annually.
Q. Am I worse off with more months?
In total cost, yes. The total fee grows roughly in proportion to the number of months. Even a 1%pp rate reduction makes a difference: dropping from 15% to 14% on 1.2M / 12 months saves 6,500 KRW.
Q. My card issuer's billed amount differs from this result.
Card issuers use daily accrual: balance x annual rate x usage days / 365. Usage days vary each installment. This calculator defaults to monthly accrual (annual rate / 12), which can differ from the billed amount by a few thousand KRW.
The default rate 15.0% is illustrative. Actual installment fee rates vary by card issuer, plan length and credit score within 5.5%–19.9% annually. Look up your card's actual rate on the Credit Finance Association's disclosure portal or your card issuer's app. Card issuers calculate on actual usage days (daily accrual), so this result may differ by a few thousand KRW.
The default values and their sources are available on the rate sources page.