Put a spare 50 million won against a Korean mortgage and the prepayment penalty comes to 137,500 won — that is a loan 18 months old at a 0.55% fee rate. But leave that 50 million in your account and carry the loan just 24 more days, and the extra interest costs you exactly the same amount. Pay the penalty now, or wait out the three years until it disappears? This article works out where the break-even day actually falls.
The break-even is 24 days
Line the two costs up and the answer appears immediately. The setup: 50,000,000 won repaid · 0.55% fee rate · 3-year fee period · 18 months elapsed. For the loan rate I used the Bank of Korea's figure for May 2026 — 4.19% a year on newly extended bank loans.
- Repay now — 50,000,000 × 0.55% × (18 months remaining ÷ 36-month fee period) = 137,500 won, paid once.
- Don't repay — 4.19% keeps running on that 50,000,000. That is 2,095,000 won a year, or 5,740 won a day.
- 137,500 ÷ 5,740 = 24.0 days. Delay repayment beyond 24 days and the extra interest exceeds the penalty you saved.
The important part is that the principal cancels out of the equation. The break-even in days is simply 365 × fee rate × (remaining ÷ fee period) ÷ annual interest rate. Repay 50 million or 300 million and the crossing point is the same 24th day. People assume a bigger repayment means a bigger penalty and therefore a worse deal — but a bigger repayment also saves proportionally more interest, so the verdict never moves.
Repaying now versus waiting out the three years
The two options are different in kind. One is a fixed cost you pay once; the other is a variable cost that accrues daily. The fixed one shrinks as time passes. The variable one grows.
| Item | Repay now | Wait until year 3 | What separates them |
|---|---|---|---|
| Penalty | 137,500 won, once | 0 won | Waiting saves this, for certain |
| Interest | Stops today | Runs for another 18 months | Waiting costs 3,142,500 won |
| Nature of the cost | Fixed, shrinking with time | Variable, growing with time | Where the two lines cross = break-even |
| Use of the cash | Locked into the loan | Free for deposits or investing | Flips only if your return beats the loan rate |
| Break-even | 24 days (at 18 months elapsed) | Delay longer and you lose | |
That 3,142,500 won is what 4.19% costs on 50 million over 18 months — more than twenty-two times the 137,500 won penalty. Sitting out the fee period to save 137,500 won means paying 3.1 million won for the privilege.
The ratio is not a coincidence. Rearranged, penalty ÷ interest-while-waiting = fee rate ÷ (3 × annual rate), and the remaining period cancels. 0.55% ÷ (3 × 4.19%) = 4.4%. However much of the fee period is left, the penalty is only 4.4% of the interest you would pay by waiting it out.
How the break-even moves with time elapsed
The penalty shrinks in proportion to the remaining period, so the longer you have held the loan, the shorter the break-even. Same setup (50 million · 0.55% · 3 years · 4.19%), varying only the months elapsed.
| Elapsed | Remaining | Penalty | Break-even | Verdict |
|---|---|---|---|---|
| 6 months | 30 months | 229,167 won | 40 days | Repay unless you would wait under 40 days |
| 1 year | 24 months | 183,333 won | 32 days | Repay |
| 1 year 6 months | 18 months | 137,500 won | 24 days | Repay |
| 2 years | 12 months | 91,667 won | 16 days | Repay |
| 2 years 6 months | 6 months | 45,833 won | 8 days | Repay |
| 3 years or more | 0 | 0 won | 0 days | Nothing to weigh |
The longest row here is 40 days, and even on a brand-new loan it is only 48 days. Yet at six months elapsed you would have to wait another 30 months for the penalty to vanish. Because the 4.4% ratio holds regardless of the remaining period, there is no window in which waiting wins. As long as your loan rate is above your deposit rate, spare cash does more good against the loan. To widen the comparison to investment returns, see paying down a loan versus saving or investing.
January 2025: the rate was cut by more than half
The break-even is this short partly because of a rule change. Korea's Financial Services Commission moved prepayment penalties onto an actual-cost basis, effective for new bank loans from 13 January 2025. A lender may charge only within its funding-disruption loss plus loan administration and origination costs; adding anything else is an unfair business practice under the Financial Consumer Protection Act.
| Loan type | Rate type | Before | After | Cut |
|---|---|---|---|---|
| Bank mortgage | Fixed | 1.43% | 0.56% | 0.87%p |
| Variable | 1.25% | 0.55% | 0.70%p | |
| Bank credit loan | Fixed | 0.95% | 0.12% | 0.83%p |
| Variable | 0.83% | 0.11% | 0.72%p | |
| Savings bank mortgage | Fixed | 1.64% | 1.24% | 0.40%p |
| Savings bank credit loan | Variable | 1.64% | 1.33% | 0.31%p |
Swap the old 1.25% back into the same example and the penalty becomes 312,500 won and the break-even 54 days. The reform cut it from 54 days to 24. Note the cutoff, though: it applies to loans taken out on or after 13 January 2025, and older loans keep their original terms. If your loan predates that, use the rate written in your contract. Mutual finance institutions (Nonghyup, Suhyup, forestry cooperatives) came under the same regime on 1 January 2026.
Refinancing is measured in months, not days
Paying down with spare cash and refinancing are different calculations. Refinancing does not remove the debt, it moves it to a cheaper rate, so the gain is limited to the rate difference. Below: a 300 million won balance at a 0.55% fee rate over a 3-year fee period, and how long it takes to earn the penalty back.
| Remaining | Penalty | 0.3%p cut | 0.5%p cut | 1.0%p cut |
|---|---|---|---|---|
| 30 months | 1,375,000 won | 18.3 months | 11.0 months | 5.5 months |
| 24 months | 1,100,000 won | 14.7 months | 8.8 months | 4.4 months |
| 18 months | 825,000 won | 11.0 months | 6.6 months | 3.3 months |
| 12 months | 550,000 won | 7.3 months | 4.4 months | 2.2 months |
| 6 months | 275,000 won | 3.7 months | 2.2 months | 1.1 months |
A 0.5%p cut on 300 million saves 1,500,000 won a year, so an 825,000 won penalty is recovered in 6.6 months. On a mortgage with 20 or 30 years left, recovery time is not the binding question — even the worst cell here is under two years. What actually decides it is whether the rate gap is 0.3%p or more. For the mechanics and limits, see the loan refinancing guide, or mortgage refinancing if the loan is secured on a home.
The costs the refinancing table leaves out
That table counts the penalty only. Taking out a replacement loan brings ancillary costs. The standard bank terms reviewed by Korea's Fair Trade Commission assign them like this.
| Item | Who pays | Basis |
|---|---|---|
| Stamp tax | Split 50/50, bank and borrower | Flat amount by loan size band |
| Mortgage registration tax and local education tax | Bank | — |
| Registration filing fee, judicial scrivener fee | Bank | — |
| Appraisal fee | Bank | — |
| National housing bond purchase | Borrower | Scales with the secured amount |
| Discharging the old mortgage | Borrower | — |
Under the Stamp Tax Act the bands are nil up to 50 million won · 70,000 won from 50 million to 100 million · 150,000 won from 100 million to 1 billion · 350,000 won above that. On a 300 million won loan that is 150,000 won, of which 75,000 won is yours. Add it to the table above and the 18-months-remaining, 0.5%p case stretches from 6.6 to 7.2 months — not enough to flip the verdict, but worth counting when the rate gap is near 0.3%p. With the national housing bond, the real cost is the discount loss when you sell it back immediately, and that depends on the bond's market price on the day.
Three ways the penalty becomes zero
Before working out a break-even, check whether the penalty can be avoided outright.
- The fee period expires. The Financial Services Commission allows a prepayment penalty only where repayment falls within three years of the loan contract. Check the disbursement date — this is the cleanest route.
- An annual fee-free repayment allowance. Some banks and products let you repay a set share of principal each year at no charge. It is not universal, so confirm it in your contract or with the branch.
- The right to request a rate cut. If all you want is a lower rate, you do not need to move the loan. Article 30-2 of the Banking Act lets a borrower request a rate reduction when their credit standing improves — increased assets, a higher credit rating or personal credit score — and obliges the bank to inform borrowers that the right exists. It was added in December 2018 and took effect on 12 June 2019. Because the loan does not move, no prepayment penalty arises.
Which side you land on
- You have spare cash and your loan rate beats your deposit rate — repay now. The penalty is 4.4% of the interest you would pay by waiting. There is nothing to wait for.
- You hold several loans — start with the highest rate. The spread between fee rates (around 0.55%) is far smaller than the spread between interest rates (4-6% a year). A loan carrying a penalty still comes first if its rate is higher.
- The full amount is too much — repay part of it. The penalty applies only to the principal you actually repay, and the interest drops immediately in proportion.
- You only want a lower rate — use the rate-cut request first. No penalty, no ancillary costs.
- The rate gap is 0.3%p or more — refinance. Recovery stays under two years even in the worst case above.
- The rate gap is 0.2%p or less — stay put. Once stamp tax and bond discount losses land on top of the penalty, recovery drags out.
- Repaying would drain your emergency fund — don't. That is a liquidity question, not a break-even question. Borrowing again in a hurry costs more than the loan you just paid off.
When this comparison does not hold
- Loans taken before 13 January 2025. The pre-reform rates (1.2-1.4% on mortgages) still apply. The break-even roughly doubles — to about 54 days — but the conclusion does not change.
- Products with a fee period other than three years. Every calculation here assumes 36 months. Use whatever your contract says.
- Banks that compute by exact days. This article counts the remaining period in whole months; a real invoice will differ by a few days' worth.
- A guaranteed return above your loan rate. If your spare cash can reliably clear 4%-plus, not repaying wins. "Reliably" is the condition.
- Repayment that voids another benefit. Some policy-backed or preferential-rate products lose their terms when repaid early or refinanced.
Sources and where to check
- Financial Services Commission — reform of the prepayment penalty calculation regime (effective for new bank loans from 13 January 2025; actual-cost basis; before-and-after rate table)
- Financial Services Commission — advance notice of the supervisory regulation change (background and the definition of allowable cost items)
- Bank of Korea — weighted average interest rates, May 2026 (4.19% a year on newly extended loans; 4.31% on outstanding balances)
- Financial Supervisory Service — Financial Products at a Glance, mortgage comparison (prepayment penalty shown in each product's detail view)
- Banking Act Article 30-2 (request for interest rate reduction) — added 11 December 2018, effective 12 June 2019. Read via the Korea Legislation Research Institute's Statutes of the Republic of Korea.
- Fair Trade Commission standard bank terms (14 April 2011) — allocation of mortgage registration costs. Read via the KDI Economic Information and Education Center reprint.
Written as of July 2026. Rates, effective dates and cost allocations are taken from the sources above; every penalty and break-even figure was cross-checked to the won against both the calculator and an independent computation. One caveat: the penalty formula (principal × rate × remaining ÷ fee period) is published by banks, not written out in the FSC or FSS regulations themselves. A single official table comparing every bank's fee rate could not be located on a public-agency page, so none is reproduced here. Confirm your own rate, fee period and waiver terms in your loan contract and with your lender. This is not financial advice. To model the total interest yourself, use the loan interest calculator.
