Mortgage Calculator

LTV (Loan-to-Value ratio) is the loan amount divided by the appraised home price, expressed as a percentage. In Korea, financial regulators set maximum LTV limits of 40–70% depending on whether the property is in a regulated area (투기과열지구, 조정대상지역) or non-regulated area. If your calculated LTV exceeds 70%, the tool shows a warning indicating the loan may be difficult to obtain.

DTI (Debt-to-Income ratio) is the total annual loan repayment divided by annual gross income. It measures how much of your income goes toward debt repayment. Korean mortgage regulations require DTI to stay below 40–60% depending on the borrower's situation and the property's regulatory classification. A DTI above 60% triggers a warning in the calculator.

LTV measures the loan amount relative to the property value. DSR (Debt Service Ratio, 총부채원리금상환비율) measures total debt repayment obligations across all loans relative to income. The calculator computes DTI (which is closely related to DSR for single-loan scenarios). For multi-loan DSR calculations, consult your bank directly.

The Equal Payment method uses the standard annuity formula: M = L × r × (1+r)^n / ((1+r)^n − 1), where L is the loan amount (home price minus down payment), r is the monthly interest rate (annual rate / 12 / 100), and n is the loan term in months. This gives a fixed monthly payment that covers both principal and interest.

Equal payment (원리금균등) provides stable, predictable monthly payments — the same amount every month. Equal principal (원금균등) has higher initial payments that decrease over time, but results in lower total interest paid over the loan life. Equal principal is more economical long-term, but may be harder to qualify for since banks assess affordability based on the first month's (highest) payment.

For regulated areas in Korea, a minimum down payment of 30–60% of the home price may be required depending on the loan type and property value. For non-regulated areas, LTV up to 70% is generally permitted, meaning a 30% down payment. The calculator shows your exact LTV for any down payment amount you enter.

The calculator is designed for standard mortgage (담보대출) scenarios where you are purchasing a property. Jeonse loans have different structures and are not directly modeled here. However, you can use the loan amount field to simulate a jeonse loan amount and the interest rate and term fields to estimate your repayment burden.

A common rule of thumb is that your housing costs (monthly mortgage payment) should not exceed 28–30% of your gross monthly income, and your total debt obligations (DTI) should stay below 36–43%. This calculator shows your DTI automatically when you enter your annual income, giving you an immediate affordability signal alongside the regulatory thresholds.

Didimol Loan (디딤돌 대출) is a Korean government-backed mortgage for low-to-moderate income owner-occupiers. Eligibility requires annual household income ≤ ₩60M (or ≤ ₩70M for newlyweds and families with two or more children), home price ≤ ₩500M, and no current home ownership. It offers a long-term fixed rate of approximately 2.35–3.95% p.a. with LTV up to 70% and DTI up to 60%, making it one of the most affordable loan products in Korea for eligible borrowers.

The Bogeumjari Loan (보금자리론) is another Korea Housing Finance Corporation product funded through mortgage-backed securities (MBS). Compared with Didimol, the income cap is slightly higher (≤ ₩70M; ≤ ₩85M for newlyweds/two-child families) and the home price limit is ₩600M. Both products offer long-term fixed rates and LTV up to 70%, but Bogeumjari may offer more flexibility in loan term. The Conforming Loan (적격대출), issued by commercial banks under HF standards, has no income cap and allows home prices up to ₩900M, making it suitable for middle-income buyers who exceed Didimol/Bogeumjari limits.

The Max Loan Calculator uses two constraints simultaneously. For LTV: max loan = property value × LTV limit. For DTI: it solves the annuity formula in reverse — given annual income × DTI limit as the maximum allowable annual repayment, it derives the maximum loan principal that would produce that payment at the specified rate and term. The effective maximum is the smaller of the two, and the calculator tells you which constraint is binding and what minimum down payment you need.