Loan & Real Estate Calculators

Loan Interest Calculator

Compare the monthly payment and total interest for the three repayment methods (equal payment, equal principal and bullet) at once.

Calculated in your browser only · inputs are not savedBased on standard formulas · enter your own rates and fees

Enter your values and press Calculate interest

Monthly payment (equal payment)

View repayment schedule

Compare repayment methods

The same loan costs different amounts of interest depending on how you repay it

With equal payment you repay the same amount each month, and with equal principal you repay the same principal each month. With a bullet loan you pay only interest and repay the whole principal at maturity.

Enter loan terms
Enter the loan amount, annual interest rate and term. If there is a grace period, enter that too.
Compare the three methods
Compare the first month's payment and total interest at once. Click a card to see the schedule for that method.
Check the schedule
See the principal, interest and remaining balance for each payment in a table and chart.

Formulas

Monthly rate r = annual rate ÷ 12, number of months n Equal payment monthly amount = loan × r × (1+r)ⁿ ÷ ((1+r)ⁿ − 1) Equal principal monthly principal = loan ÷ n, monthly interest = remaining principal × r Bullet monthly interest = loan × r, with the full principal repaid at maturity

The calculation assumes a fixed rate. With a floating-rate loan, your payment changes each time the rate changes. Banks often calculate interest daily, so the actual amount may differ by a few won to a few hundred won.

The early repayment fee is usually calculated as early repayment amount × fee rate × (fee-free period − elapsed period) ÷ fee-free period, and the rate and fee-free period differ by loan contract.

FAQ

Which is better, equal payment or equal principal?

Equal principal costs less total interest because you pay the principal down faster. However, initial payments are larger, so the monthly burden is heavier. Equal payment is the same amount every month, which makes budgeting easier.

What changes if I have a grace period?

Interest-only payments during the grace period reduce your early burden, but the repayment period for principal becomes shorter, so later monthly payments and total interest go up.

When is bullet repayment used?

It is mainly used for jeonse deposit loans and short-term credit loans. You pay only interest each month and repay the whole principal at maturity, so you need to prepare the maturity repayment funds in advance.

Why does the result differ slightly from my actual bank payment?

Banks calculate interest on actual days (daily accrual on a 365-day basis), and their rounding down to the won may differ. This calculator gives a reference value based on a monthly formula.

How much can I borrow?

The limit is set by your annual debt service ratio relative to income (DSR) and LTV rules. Enter your existing loans in the DSR Calculator to check your additional limit.

Results are estimates based on your inputs and simplified assumptions, and are for reference only, not a basis for investment decisions.