Loan Calculator
Compare 3 Korean loan repayment types in one place. Monthly schedule with principal, interest, and balance breakdown.
Repayment Plan
Enter principal, rate, and period.
What this tool does
The Korean loan calculator compares the three most common Korean repayment types — equal payment (same monthly amount), equal principal (high to low), and balloon (interest only with principal at maturity) — in one screen, with a monthly amortization schedule. The same standard formulas apply to mortgages, credit loans, jeonse-deposit loans, and auto installments. Prepayment fees, stamp duty, and DSR limits are not included.
Who uses this
- Mortgage planning: compare total interest of equal payment vs equal principal
- Credit loan: see monthly burden differences for balloon vs amortized
- Jeonse deposit loan: confirm the interest-only monthly + balloon at maturity
- Refinancing: enter remaining balance and new rate to see new payment
- Long-term planning: track balance at 1, 5, 10 years into a 30-year mortgage
How to use (4 steps)
- 1Enter the loan principal in won. KRW 400M mortgage = 400000000; KRW 50M credit loan = 50000000.
- 2Enter the loan term in years. Korean mortgages are usually 30 years, credit loans 1-5 years, jeonse loans 2 years.
- 3Enter the annual rate (%). 4.5% = enter 4.5. For variable rates, use the current rate; simulate upward scenarios separately.
- 4Select one of the three repayment types and click Calculate. You'll see first/last payment, total interest, total payment, and the amortization schedule (sampled every 6 months for terms over 60 months).
Formulas (3 repayment types)
Equal payment: M = P × r(1+r)^n / ((1+r)^n − 1) P = principal, r = monthly rate (annual / 12), n = total months Monthly amount M is constant. Early payments lean interest-heavy, later lean principal-heavy. Equal principal: monthly principal = P/n, monthly interest = balance × r First payment = P/n + P×r (largest) Last payment = P/n + (P/n)×r (smallest) Total interest is ~4-5% less than equal payment. Balloon: monthly = P × r (interest only) Last payment = P × r + P (full principal at maturity) Highest total interest but lightest monthly burden. Common for Korean credit and jeonse loans.
Real examples
Example 1: KRW 400M / 30 years / 4.5% / equal payment
Monthly rate 0.375%, 360 payments. Monthly amount ~KRW 2,026,920. Total payment ~KRW 729.7M, total interest ~KRW 329.7M — nearly equal to the principal over 30 years.
Example 2: Same terms, equal principal comparison
First payment KRW 2,611,111 (principal 1.11M + interest 1.5M), last payment KRW 1,115,278. Total interest ~KRW 270.7M — about KRW 59M less than equal payment. But the first 5 years cost ~KRW 500K more per month.
Example 3: KRW 50M / 3 years / 6% / balloon
Monthly interest = 50M × 6%/12 = KRW 250,000. 36 months of interest only, then KRW 50M + final KRW 250K at maturity. Total interest KRW 9M. Light monthly but the maturity lump sum needs a clear repayment source.
Frequently asked questions
Equal payment vs equal principal — which is better?+
By total interest, equal principal saves about 4-5%. But the first 5-10 years carry a much heavier monthly burden. If early cash flow is tight, choose equal payment; if you have early room and want long-term savings, choose equal principal.
Why is balloon repayment common in Korea?+
Credit loans and jeonse-deposit loans run short (1-3 years) for a specific large need. Minimizing monthly principal payments and repaying at maturity from another source (deposit refund, sale proceeds) fits this pattern.
How are prepayment fees handled?+
This calculator does not include them. Korean prepayment fees are typically 0.5-1.5% of the outstanding balance and apply within the first 3 years. When refinancing, subtract fees from interest savings to see the real benefit.
Where do I check the DSR (debt service ratio) limit?+
DSR is annual principal+interest divided by annual income, capped at 40% for banks and 50% for secondary lenders. Multiply this calculator's monthly payment by 12 and divide by your annual income, summing across all debts.
How do I handle variable-rate loans?+
Variable rates reset every 6 or 12 months. This calculator assumes a single rate, so simulate upward scenarios (e.g., +1% in 1 year) conservatively by re-running with the adjusted rate.
Why do first and last payments differ?+
Equal payment is constant; equal principal's last payment is ~30-40% smaller as the balance shrinks; balloon's monthly is the same but the last payment adds the full principal.
How much does early repayment save?+
Paying off a 30-year mortgage at year 10 eliminates years 11-30 of interest entirely. Prepayment fees typically apply within 5 years (0.5-1.5%), then disappear. Early repayment is a powerful saving tool.
Cautions
- •Prepayment fees, stamp duty, and mortgage registration fees are not included.
- •The DSR limit (40% for banks) must be checked separately.
- •Variable rates assume a single rate — simulate upward scenarios separately.
- •Monthly rate r = annual rate / 12 (Korean standard simple-rate division).
- •Results are for planning. Actual terms are confirmed by the lender.
Last reviewed: 2026-05-23