DSR/DTI Calculator

DSR (Debt Service Ratio) is the ratio of a borrower's total annual principal and interest repayments across all loans divided by their annual income. Unlike DTI, DSR includes the full principal and interest payments for every type of debt — mortgages, credit loans, auto loans, card loans, student loans, and more. For example, if your annual income is 50 million KRW and your total annual loan repayments are 20 million KRW, your DSR is 40%. DTI (Debt-to-Income Ratio) is a similar metric but with a key difference: it counts the full principal and interest payments only for mortgage loans, while for all other debts, it counts only the annual interest payments (excluding principal repayment). This means that under the same loan conditions, DTI will always be lower than DSR, making DSR the stricter measure. Since 2018, South Korean financial regulators have adopted DSR as the primary loan assessment metric. Currently, DSR regulations apply to all borrowers whose total outstanding loans exceed 100 million KRW. The regulation is designed to manage household debt soundness and prevent excessive borrowing beyond a borrower's actual repayment capacity. Understanding both ratios is essential for anyone planning to take out a mortgage or other significant loans in South Korea.

1. Select either DSR or DTI mode from the tabs at the top. DSR reflects principal and interest for all loans, while DTI reflects mortgage principal and interest plus only the interest on other loans. 2. Enter your annual income. For salaried employees, enter your pre-tax annual salary. For self-employed individuals, enter income as reported on your comprehensive income tax return. 3. Select your regulatory zone. Speculative/Overheated zones have a DSR limit of 40% and DTI limit of 40%. Adjusted zones have DSR 40% and DTI 50%. Non-regulated zones have DSR 40% and DTI 60%. The calculator will show whether you pass or exceed the applicable limit. 4. Enter your loan details. For each loan, specify the type (mortgage, credit, auto, card, or other), outstanding balance, annual interest rate, remaining term in months, and repayment method (equal payment, equal principal, or bullet/lump-sum). 5. If you have multiple loans, click 'Add Loan' to add up to 10 loans. In DSR mode, you can also enable Stress DSR to see how your ratio would change if interest rates increase by the regulatory stress rate adder.

■ DSR Formula DSR (%) = (Sum of Annual Principal + Interest for ALL Loans) ÷ Annual Income × 100 All debts are included with both principal and interest repayments summed up. ■ DTI Formula DTI (%) = (Mortgage Annual P&I + Other Loans Annual Interest Only) ÷ Annual Income × 100 Mortgage loans include principal and interest, but other loans only count interest payments. ■ Annual Repayment by Repayment Method • Equal Payment (Annuity): Monthly Payment = Principal × Monthly Rate × (1+Monthly Rate)^Months ÷ ((1+Monthly Rate)^Months - 1), Annual = Monthly × 12 • Equal Principal: Monthly Principal = Total Principal ÷ Total Months, interest decreases as balance reduces. First 12 months are summed. • Bullet (Lump-sum): Annual Repayment = Annual Interest + (Principal ÷ Term in Years). Although the actual principal is repaid at maturity, for DSR calculation purposes, the principal is amortized evenly across the loan term. ■ Stress DSR Stress DSR recalculates DSR by adding a stress interest rate on top of the actual loan rate. Capital/regulated areas add +3.0%p and non-capital areas add +0.75%p. This system preemptively reflects the increased repayment burden if interest rates rise in the future.

1. Prioritize High-Interest Debt: To reduce your DSR effectively, pay off high-interest loans first — credit loans and card loans typically carry the highest rates. Paying down the same amount on a high-interest loan has a much larger impact on your annual repayment burden. 2. Repayment Method Matters: Bullet (lump-sum) loans may seem easier with lower monthly payments, but for DSR purposes, the principal is annualized over the loan term, which can make your DSR surprisingly high. Equal payment (annuity) loans are generally more favorable for both long-term interest costs and DSR calculations. 3. Leverage Loan Term: Extending your repayment period reduces monthly payments and lowers DSR. However, this increases total interest costs, so find the right balance between manageable DSR and reasonable total cost. 4. Prepare Income Documentation: Recognized income for DSR includes employment income (withholding receipts), business income (tax returns), pension income (pension statements), and rental income (lease contracts). The more income you can verify, the better your DSR ratio. 5. Close Unused Credit Lines: Unused overdraft accounts and card loan limits still count toward DSR. Cancel unnecessary credit lines before applying for a new loan to improve your ratio. 6. Plan for Stress DSR: Since July 2025, Stress DSR Phase 3 adds up to 3.0%p for capital/regulated area mortgages. Always factor in potential rate increases when planning your loans. 7. Consider Joint Applications: Combining spousal income for DSR calculation can increase your borrowing capacity. However, review the tax implications of joint ownership (acquisition tax, comprehensive real estate tax) before deciding.