📊 DTI Calculator (Debt-to-Income, Korea)
Calculate the share of your income that goes to mortgage payments and interest on other loans — Korea’s DTI ratio.
How to use
Enter your pre-tax annual income and the terms of the new mortgage (amount, rate, term, repayment type); the annual payments are calculated for you. If you already have a mortgage, enter its annual principal and interest. For other debt — personal loans, car loans — enter only the annual interest. Change the DTI limit to see the largest mortgage you could take under it.
What is DTI?
DTI (debt-to-income, chongbuchae sanghwan biyul in Korea) is the share of your annual income spent on mortgage principal and interest plus interest on other loans. Korea introduced it in 2005 as a mortgage rule that looks at ability to repay, unlike LTV, which looks at the home’s value. Regulated areas have used 40%, other areas roughly 50–60%.
Note that the Korean DTI differs from the US “back-end DTI” lenders quote (often 36–43% of monthly gross income including all minimum debt payments). Korea’s DTI counts only the interest on non-mortgage loans; the stricter Korean measure that counts everything is DSR.
How it is calculated
DTI (%) = (new mortgage annual payments + existing mortgage annual payments + annual interest on other loans) ÷ annual income × 100
Example: income ₩60M, a ₩300M mortgage (4%, 30 years, level payment) → annual payments about ₩17.19M, plus ₩1.5M of personal-loan interest → (17.19 + 1.5) ÷ 60 ≈ 31.1%.
DTI vs. DSR
| Item | DTI | DSR |
|---|---|---|
| Mortgages | Principal + interest | Principal + interest |
| Personal and other loans | Interest only | Principal + interest |
| Limit | 40–60% by region | 40% banks, 50% non-banks |
| Role today | Secondary check | Sets your real limit |
The key difference is whether other loans’ principal counts. A ₩50M personal loan adds only a few million won of interest to DTI, but DSR also adds principal (₩10M a year assuming 5-year repayment), so the ratio jumps. Since borrower-level DSR was expanded from 2021, most Korean mortgage limits are decided by DSR and DTI is reviewed alongside it.
How to lower your DTI
- Take a longer term to cut annual payments (total interest goes up)
- Pay down personal loans or other debt first
- Use a product that allows combining a spouse’s income
Income for foreign residents
Banks recognize income they can verify in Korea: for employees, total pay on the withholding tax receipt; for the self-employed, income on the income amount certificate from Hometax. Overseas income is rarely recognized unless it is reported in Korea.
Korean lending rules change often with government housing measures. Figures are examples as of October 2026; your real limit depends on the bank’s review (how your income is recognized, credit score, property type, policy loan eligibility and, for foreign nationals, your visa and residence status). Always confirm with the Financial Services Commission announcements and the bank you plan to use.