What Is the Loan Interest Calculator?

The Loan Interest Calculator helps you quickly figure out your monthly payment, total repayment, and total interest for different repayment methods—without doing the math yourself.

Just enter the loan amount (KRW), annual interest rate (%), repayment period (months), and choose a repayment method. You’ll instantly see how much you’ll pay and how interest changes by method.

Supported Repayment Methods

• Equal Principal & Interest: Same payment every month. Easy to manage.
• Equal Principal: Same principal each month; interest decreases over time. Higher at first, lower total interest overall.
• Lump-Sum at Maturity: Pay only interest monthly; repay the full principal at the end.

Formulas

1. Monthly Rate = (Annual Rate ÷ 12) ÷ 100
2. Equal P&I = P × (r × (1 + r)ⁿ) ÷ ((1 + r)ⁿ − 1)
3. Equal Principal = (P ÷ n) + (Remaining Principal × Monthly Rate)
4. Lump-Sum = Monthly interest only + Full principal at maturity

* Provided for free by No1Item.com. Optimized for both PC and mobile.