Loan Interest Calculator
Enter principal, rate, term, and repayment type to compute monthly payment and total interest for any Korean loan structure.
e.g., 30 years = 360, 10 years = 120, 1 year = 12
Same amount (principal + interest) every month. Most common.
Monthly payment (fixed)
536,822KRW
Total interest: 93,255,920 KRW
- First month payment
- 536,822KRW
- Last month payment
- 536,822KRW
- Total payment
- 193,255,920KRW
- Total interest
- 93,255,920KRW
- Total interest / principal
- 93.26%
- Equal-payment method — same monthly amount
Comparing repayment methods
Korean loans use three main repayment structures. Equal payment makes monthly budgeting easy with one fixed amount. Equal principal lowers the bill each month and minimizes total interest. Bullet keeps cash flow free during the term but pays the most interest because the full principal stays outstanding. Same loan terms produce: equal-principal interest < equal-payment interest < bullet interest.
Formulas
Equal payment: M = P × i × (1+i)^n / ((1+i)^n − 1)
Equal principal first month: P/n + P × i / last month: P/n + (P/n) × i / total interest: P × i × (n+1) / 2
Bullet: monthly interest = P × i, final month = P × i + P
Which one suits you?
Long mortgages typically use equal payment for predictability. If you have spare cash and want to minimize total interest, equal principal is better. Bullet is only sensible when you have a defined exit (sale, settlement) within 6–12 months.
Frequently asked questions
- How do floating rates work?
- This calculator assumes a fixed rate. For floating, re-run with the new rate and remaining term whenever the rate resets (commonly 6- or 12-month cycles). The HF or bank simulators handle this more precisely.
- Grace period (interest-only)?
- During grace, you pay interest only; afterward you repay principal over the remaining term in equal payment or equal principal mode. This calculator assumes no grace — repayment starts month one.
- What about prepayment penalties?
- Korean banks typically charge 0.5–1.5% on the prepaid balance for the first 3 years. This calculator assumes regular payment until maturity.
- How do I check DSR / DTI?
- DSR divides annualized total-loan principal+interest by yearly income; DTI uses mortgage P+I plus other-loan interest only. Take this calculator's monthly payment × 12 and compare against your annual income for a rough DSR.
Reference only. Fixed-rate, on-time payment assumptions. Floating rates, grace periods, prepayment penalties, daily accrual, quarterly/semiannual interest, spread changes, and rate concessions are not modeled. Confirm the exact schedule with HF or your lender's simulator.