Loan Refinancing Calculator

Compare current and new loan payments, interest savings, fees, and refinancing breakeven.

Refinancing inputs

Compare current and new loan payments after fees.

Current balance

Current APR

New APR

Remaining term

years

Refinance fee

Fixed closing costs

Monthly savings

$190

Net savings after costs

$37,559

Breakeven

1 yr 7 mo

Refinance costs

$3,540

A refinance usually makes sense only when the breakeven point is earlier than the time you expect to keep the loan.

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What is the loan refinancing calculator?

Refinancing means repaying an existing loan with a new loan that has a lower rate, better maturity, or more suitable repayment structure. This calculator compares monthly savings, refinancing costs, prepayment fees, and break-even timing.

Break-even formula

Break-even months = total refinancing cost / monthly interest saving. A refinance is easier to justify when the new rate is at least 0.5 percentage points lower and the remaining term is long enough to recover the costs.

Prepayment fee and 2025 revision

Fee formula and waiver

Prepayment fee = prepaid principal x fee rate x remaining days / loan-period days.
After the 2025 Financial Consumer Protection Act revision, prepayment fees are uniformly waived after 3 years, or 1,095 days, across banks in the Korean source.
Refinancing is especially attractive after the 3-year fee exemption period has passed.
Switching from variable to fixed can also be rational when rates are expected to rise, even if the headline rate saving is smaller.

Reference fee rates after January 13, 2025

Mortgage loans: fixed 0.6%, variable 0.7%, mixed 0.6%.
Credit loans: fixed 0.4%, variable 0.1%.
Jeonse loans: variable 0.5%.
Stamp-tax customer share is KRW 0 up to KRW 50,000,000, KRW 35,000 for KRW 50,000,000 to KRW 100,000,000, KRW 75,000 for KRW 100,000,000 to KRW 1,000,000,000, and KRW 175,000 above KRW 1,000,000,000.

Mortgage example and extra costs

Worked refinance example

For a KRW 300,000,000 loan, current rate 4.5%, new rate 3.5%, remaining term 25 years, and equal principal-and-interest repayment, the Korean example shows current monthly payment about KRW 1,668,000 and new monthly payment about KRW 1,506,000. Monthly saving is about KRW 162,000. If total refinancing cost is KRW 1,600,000, break-even is about 10 months.

Additional checks

Mortgage refinancing may add registration license tax at collateral amount x 0.2%, local education tax at 20% of registration tax, legal fees around KRW 200,000 to KRW 400,000, and national housing bond discount cost.
Typical mortgage incidental costs in the guide are often around KRW 300,000 to KRW 500,000 before case-specific items.
The borrower must still satisfy DSR, commonly 40% for banks.
Extending maturity can reduce monthly burden and DSR pressure, but it can increase total lifetime interest.