About this tool
This loan interest calculator compares the three repayment methods Korean banks offer. With equal payment (์๋ฆฌ๊ธ๊ท ๋ฑ์ํ) you pay the same amount every month: payment = principal x r / (1 - (1 + r)^-n), where r is the annual rate divided by 12 and n is the number of months. With equal principal (์๊ธ๊ท ๋ฑ์ํ) you repay the same principal each month plus interest on the remaining balance, so early payments are larger and total interest is lower. With bullet repayment (๋ง๊ธฐ์ผ์์ํ) you pay only interest each month and return the whole principal at maturity, which has the lowest monthly burden but the highest total interest. For example, borrowing 100,000,000 won at 5% for 360 months with equal payment costs 536,822 won a month and about 93.3 million won in total interest, while equal principal starts at 694,444 won and totals about 75.2 million won of interest. Interest is rounded to the won every month and the final payment absorbs rounding, so a bank statement that counts by days can differ slightly. Early-repayment fees, preferential rates, floating-rate changes and fees are not included. The result is a reference estimate and does not replace advice from a financial professional.
How to use
- Enter the loan amount in won and the annual interest rate.
- Enter the term in months (360 months is 30 years).
- Pick a repayment method and read the monthly payment, total interest and total repayment.
- Compare the three methods in the table and open the full schedule if you need it.