Loan Repayment Calculator

Applies the equal-payment, equal-principal and bullet formulas to build a month-by-month schedule in real time.

Loan amount

KRW

Term

Annual rate

Repayment method

Equal payments (annuity) Same total (principal + interest) every month Equal principal Fixed principal each month + interest on the remaining balance Bullet (interest-only) Pay only interest monthly, repay the full principal at maturity

Total repayment (principal + interest)

0 KRW

Principal 0 KRW

Total interest 0 KRW

1st monthly payment: 0 KRW

Interest as % of principal: 0.00% of principal

Repayment schedule

No.	Payment	Principal	Interest	Balance

What this tool does

Enter the loan amount, term in months and annual interest rate, pick a repayment method (equal payments, equal principal or interest-only with a balloon at maturity), and you instantly see the total repaid, total interest, first monthly payment, interest as a share of principal and a month-by-month schedule. The schedule downloads as a CSV file that opens in Excel. Amounts are labelled in Korean won, but the formulas work for any currency. Use it to compare monthly burden and total interest for the same loan.

How it is calculated

It uses a monthly rate of annual rate ÷ 12 and the number of months. Equal payments: payment = principal × r × (1 + r)^n ÷ ((1 + r)^n − 1), the same every month, with interest = remaining balance × r. Equal principal: you repay principal ÷ n each month plus interest on the remaining balance. Interest-only: you pay principal × r each month and the whole principal in the last month. With the default 50,000,000 won over 24 months at 4.5%, equal payments come to about 2.18 million a month and about 2.38 million in interest; equal principal starts near 2.27 million and falls to about 2.09 million with about 2.34 million in interest; interest-only is 187,500 a month and 4.5 million in interest. The last instalment absorbs rounding so the balance ends at zero.

Enter the loan amount (default 50,000,000)

Enter the term in months; three years is 36

Enter the annual rate as a percentage, e.g. 4.5

Choose one of the three methods; the summary and schedule update immediately

Check each month's payment, principal, interest and balance, and download the CSV if needed

Things to know

Total interest is usually interest-only > equal payments > equal principal, while the early monthly burden is highest for equal principal and lowest for interest-only.

In an equal-payment schedule interest dominates early and principal later, so the point where half the principal is left comes after the halfway month.

Enter the term in months, not years; typing 3 means a three-month loan.

A rate of 0 gives an interest-free split of principal over the months, handy for planning instalments.

Real loans may add early-repayment fees, stamp duty or guarantee fees, and banks may charge interest daily, so results can differ slightly.

For a variable-rate loan, recalculate with the remaining balance and months whenever the rate changes.

The CSV includes a marker so Korean text displays correctly in Excel, and the file name includes the method.

Frequently asked questions

Which is better, equal payments or equal principal?

Equal principal costs less interest in total but has a higher first payment. Decide by what you can afford each month, and toggle between the two to compare the first payment and total interest.

What goes in the interest rate field?

The annual rate your lender quotes, as a plain percentage such as 4.5. If you get a discount, enter the final rate after it.

Why does a longer term raise total interest so much?

You pay interest for more months, and the balance shrinks more slowly so each month's interest stays larger. A shorter term raises the monthly payment but cuts total interest sharply.

Does it account for early repayment?

No. If you plan to prepay part of it, recalculate with the remaining balance and months afterwards, and check your lender's early-repayment fee.

An estimate, not professional advice. Actual loan terms and payments are set by your lender.