2026 Stress DSR Mortgage Limit Guide

Summary: Korea’s stress DSR tests a mortgage with a higher assessment rate than the rate initially offered. Your usable limit is the lower of the income-based DSR result and the property-based LTV result. Compare a normal-rate case, a stressed-rate case, and a rate-plus-two-percentage-points case before signing.

What does stress DSR mean in 2026?

DSR, or debt service ratio, divides the annual principal and interest payments on all covered debts by recognized annual income. At a simplified 40% ceiling, income of KRW 70 million provides an annual debt-service budget of KRW 28 million. Existing credit loans, card loans, and qualifying instalment debt consume part of that budget before a new mortgage is calculated.

Stress DSR does not increase the interest you actually pay. It adds a hypothetical stress rate only for affordability assessment. If a mortgage is offered at 4.0% but assessed at 5.5%, the bank calculates the maximum principal with 5.5%. A higher assessment rate produces a lower principal for the same monthly payment and maturity.

Variable, mixed, and periodic-rate loans

Variable loans generally receive the largest stress-rate weight because their payment can change quickly. A mixed loan fixes the rate for an initial period and later becomes variable. A periodic-rate loan resets at scheduled intervals. A longer fixed or reset period may improve the assessed limit, but its quoted rate can be higher. A larger approval limit and a lower total borrowing cost are different goals.

How is the mortgage limit calculated?

First calculate the annual budget: recognized income multiplied by the applicable DSR ceiling, minus annual payments on existing debts. Divide the remaining budget by twelve. For an amortizing loan, approximate principal P from monthly payment A, monthly assessment rate r, and number of payments n: P = A × [1 − (1 + r)^(-n)] ÷ r.

Use the DSR calculator for the income limit, the LTV calculator for the collateral limit, and the loan calculator for monthly payments. The smallest result is the useful planning ceiling, subject to the lender’s underwriting.

Income examples

Assume a 40% DSR, no existing debt, 30-year equal payments, and compare 4.0% with a 5.5% assessment rate. Annual income of KRW 50 million provides KRW 20 million for annual debt service: the approximate limit falls from KRW 349 million to KRW 294 million. At KRW 70 million income, it falls from about KRW 489 million to KRW 412 million. At KRW 100 million income, it falls from about KRW 698 million to KRW 588 million.

If the KRW 70 million borrower already pays KRW 6 million per year on other debt, only KRW 22 million remains. Under the same 5.5%, 30-year assumptions, the new mortgage estimate falls to roughly the low KRW 300 millions. This is why taking a car instalment or a credit loan shortly before a home purchase can materially change the closing plan.

Which rate type should you choose?

Do not choose solely to maximize approval. Calculate payments at the quoted rate, at the lender’s assessment rate, and after a two-point rise. Then test a 10% income decline and six months of essential expenses. A longer fixed period may protect cash flow, while a variable loan may start cheaper but exposes the household to faster payment changes.

Bank consultation checklist

• Prepare two years of income evidence and a complete debt list.
• Confirm whether unused credit-line limits affect assessment.
• Ask for variable, mixed, and periodic-rate quotations on identical terms.
• Record the actual rate, stress treatment, monthly payment, total interest, and early-repayment charge.
• Verify LTV rules for the location, home value, and number of homes owned.
• Keep a 10–15% financing buffer and discuss a loan-denial clause before contracting.

Practical insight

The important result is not the largest number a calculator displays. Stress DSR shifts future rate risk into today’s approval process. The same income can therefore produce a difference of tens of millions of won depending on existing debt and rate structure. Save three scenarios and rebuild the household budget using the most conservative monthly payment. Compare that result with LTV, choose the smaller ceiling, and keep cash for closing costs and emergencies. This process reduces both funding failure and post-purchase cash-flow stress without requiring a prediction of house prices.

Frequently asked questions

Do I pay the stress rate? No. It is an assessment rate; the contract rate determines actual interest.

Is DSR always 40%? No. The institution, borrower, and product can change the rule or create exclusions.

Does a 40-year term always help? It can raise the limit but normally increases total interest and may have eligibility limits.

Will repaying credit debt immediately raise my limit? Often, but credit reporting can lag; obtain proof and confirm timing.

Can spouses combine income? Some joint-borrower products allow it, while the spouse’s debts may also be included.

Why does the bank differ from the calculator? Banks add recognized-income rules, collateral valuation, credit scoring, and internal limits.

Information date: 21 July 2026. This educational estimate is not a credit approval or financial advice; confirm current terms with the lender.