Korea Mortgage DSR Calculation Guide 2026 — Maximum Loan Amount Under Updated Regulations

What Is DSR and Why Does It Matter?

DSR (Debt Service Ratio, 총부채원리금상환비율) is the primary criterion Korean banks use to evaluate mortgage applications. It expresses your total annual debt repayments (principal + interest across all loans) as a percentage of your annual income.

DSR formula:

DSR (%) = (Annual repayments on all loans / Annual income) × 100

If your DSR exceeds the regulatory limit, your loan application will be rejected — regardless of your credit score or asset value.

2026 DSR Regulatory Limits

As of 2026, Korean financial regulators apply tiered DSR limits based on loan size and borrower category:

Important change from 2025: Some regions formerly classified as "regulated areas" (투기과열지구) have been reclassified, allowing slightly higher LTV (Loan-to-Value) ratios and easing effective borrowing capacity for buyers in those areas.

Step-by-Step DSR Calculation

Step 1: Calculate Annual Income

DSR uses "recognized income" — not necessarily your total gross income. Banks verify:

• Salary income: Full amount recognized
• Self-employment income: 2-year average from tax returns
• Rental income: 70% recognized
• Dividend and investment income: Generally not recognized unless consistent over 2+ years

Example: Annual salary of 60,000,000 KRW → Recognized annual income: 60,000,000 KRW

Step 2: Calculate Existing Annual Debt Repayments

Include all existing loans:

• Car loan: Monthly 500,000 × 12 = 6,000,000 KRW/year
• Personal loan: Monthly 300,000 × 12 = 3,600,000 KRW/year
• Credit card revolving balance: Treated as a 1-year installment

Example: Existing annual repayments: 9,600,000 KRW

Step 3: Determine Maximum Allowable Mortgage Payment

With a 40% DSR limit and 60,000,000 KRW annual income:

• Maximum annual repayments (all loans): 60,000,000 × 0.40 = 24,000,000 KRW
• Existing repayments: 9,600,000 KRW
• Available for mortgage: 24,000,000 − 9,600,000 = 14,400,000 KRW/year = 1,200,000 KRW/month

Step 4: Calculate Maximum Loan Amount

A mortgage payment of 1,200,000 KRW/month supports different loan amounts depending on the interest rate and term:

At 4.0% interest on a 30-year term, this household qualifies for approximately 232,000,000 KRW in mortgage financing.

DSR Calculation Example: Full Scenario

After down payment: If the property you want costs 550,000,000 KRW, you need a down payment of at least 318,000,000 KRW.

Strategies to Increase Your Borrowing Capacity

1. Pay Off High-Balance Loans Before Applying

Clearing existing loans reduces your existing annual repayments, freeing DSR capacity for the mortgage.

2. Increase Recognized Income

If your income includes non-recognized sources (investments, freelance), converting some to formally recognized structures (business registration, dividend declarations) can increase your recognized income base.

3. Choose a Longer Loan Term

A 40-year mortgage has lower monthly payments than a 30-year loan at the same rate — this allows a larger principal within the same DSR constraint.

4. Apply Under First-Time Homebuyer Programs

Korea's Bogeumjari Loan (보금자리론) and similar first-time buyer programs apply DSR of up to 60% instead of 40%, significantly expanding borrowing capacity.

5. Use the DSR Calculator

The MillionsCode Deposit Interest Calculator and similar tools can help you model how different loan sizes, interest rates, and terms affect your monthly payment and DSR.

Conclusion

DSR is the binding constraint for most Korean mortgage applicants in 2026 — more binding than credit score or property value in many cases. Understanding your DSR before engaging with banks puts you in a stronger negotiating position and prevents the frustration of late-stage application rejection. Calculate your DSR using the formula above, compare against the applicable limit, and plan your debt repayment and income documentation strategy accordingly.