INPUT LEDGER
What is known, entered, or assumed.
| Input | Value | Origin |
|---|---|---|
| Purchase price | ₩800,000,000 | Illustrative scenario |
| Cash contribution | 40% / ₩320,000,000 | User assumption |
| Loan | ₩480,000,000 at 4.0% for 30 years | User assumption |
| Management fee | ₩270,000 per month | Illustrative complex estimate |
REPRODUCIBLE CALCULATION
Follow the intermediate result.
Loan principal
Formula or rule: ₩800,000,000 × 60%
Result: ₩480,000,000
Monthly rate and periods
Formula or rule: 4.0% ÷ 12; 30 × 12
Result: 0.3333% and 360 payments
Equal monthly payment
Formula or rule: P × r(1+r)^n ÷ ((1+r)^n−1)
Result: About ₩2,291,593
Visible recurring outflow
Formula or rule: Payment + management estimate
Result: About ₩2,561,593 per month
DECISION READING
What the result means.
The purchase price alone is not a household budget. Under these assumptions, the visible recurring outflow starts near ₩2.56M before acquisition tax, brokerage, insurance, property tax, repairs, moving costs, and opportunity cost.
SENSITIVITY
What could change the answer.
- Every ₩10M change in cash contribution changes the financed principal by the same amount.
- A different rate changes all 360 scheduled payments; see the separate rate-sensitivity case.
- Complex-level management data cannot reproduce one household's seasonal usage.
BOUNDARIES
What this case does not prove.
- This is not a lender quote or an eligibility decision.
- The example does not assert that an apartment is currently listed or available.
- Public transaction and management records may be delayed, revised, cancelled, or unmatched.
OFFICIAL SOURCES
Where factual context is verified.
RELATED APT CASES
Change one assumption and compare again.
Each case keeps inputs, arithmetic, evidence, and uncertainty in separate layers.