How is the monthly repayment calculated?

The tool uses the standard reducing-balance annuity formula. Each month interest is charged on the outstanding balance and the rest of the fixed payment reduces the principal, so early payments are mostly interest and later ones mostly principal. When the rate is zero the payment is simply the loan divided by the number of months.

What rates are typical in South Korea?

Bank personal (credit) loans in Korea commonly run from about 4% to 20% a year depending on your credit grade, while fintech and savings-bank lenders often price from 7% up to around 24%. Card cash advances and card loans sit at the higher end. Your actual rate depends on your credit score and income.

What is the 40% DSR cap?

The Debt Service Ratio (DSR) rule limits your total annual loan repayments — across all borrowing — to about 40% of your annual income for most regulated borrowers. This calculator can compare this single loan's payment against 40% of your income, but the real cap counts every loan you hold, so leave headroom.

Does the schedule show how interest falls over time?

Yes. The amortisation table lists each month's interest, principal and remaining balance. You will see interest shrink and principal grow as the balance falls, which is why paying extra early — or choosing a shorter term — saves a disproportionate amount of total interest.

Is early repayment free in Korea?

Often not. Many Korean loans carry an early-repayment fee (jung-do-sang-hwan susuryo), typically a small percentage that tapers over the first few years. This tool models the scheduled repayments only; check your contract for any prepayment penalty before paying a loan off early.

South Korea Personal Loan Calculator

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This South Korea personal loan calculator shows the monthly installment, total interest and a full amortisation schedule for an unsecured loan, using Korea’s typical market rates. It can also check the repayment against the 40% DSR cap that Korean lenders apply.

How it works

The repayment uses the standard reducing-balance annuity formula:

M = P × r(1+r)^n / ((1+r)^n − 1)

where P is the loan amount, r is the monthly rate (annual rate / 12) and n is the number of months. If r is zero the payment is simply P / n. Each month, interest is charged on the outstanding balance and the remainder of the fixed payment cuts the principal:

interest_month   = balance × r
principal_month  = M − interest_month
balance          = balance − principal_month

For the DSR check, the tool compares the monthly payment against monthly income × 40%. Note the real DSR counts all your loans, not just this one.

Example

Borrowing 30,000,000 won over 36 months at 8% gives a fixed monthly payment of roughly 940,000 won and total interest in the low millions. Drop the rate to 5% or shorten the term and both the payment mix and the total interest move noticeably — the schedule makes the trade-off clear.

Notes

Rates depend on your credit grade and lender type. The 40% DSR cap aggregates every loan you hold, so leave headroom. Many Korean loans charge an early-repayment fee, which this scheduled-payment model does not include. Estimate only — confirm terms with your lender.