What this tool does
The decision behind APT
APT is TOOOLBOX's Korean apartment housing-cost analysis workspace. It is designed for a question that listing pages do not answer well: after the purchase price, deposit, rent, financing, and recurring building costs are considered together, what does living in this apartment look like on a monthly basis?
The live service combines reported apartment sale transactions with jeonse and monthly-rent transaction records. Users can narrow the analysis by region, price range, and exclusive floor area, then apply their own financing assumptions such as loan-to-value ratio, expected interest rate, loan term, and available cash.
The result is a comparison tool rather than a property advertisement. APT does not claim that a displayed apartment is currently for sale, does not predict investment returns, and does not decide whether a lender will approve a mortgage. Its role is to organize public transaction evidence and user-entered assumptions into a more understandable housing-cost comparison.
Inputs & outputs
What goes in, and what comes back
Inputs
- Province and city/district selection based on Korean legal-dong administrative codes.
- Minimum and maximum purchase budget and preferred exclusive floor-area range.
- A three-year or five-year transaction-history window for purchase-price context.
- User-entered LTV assumption, expected annual interest rate, and repayment term.
- Available-cash ratio used to test whether a candidate fits the user's financing assumptions.
Outputs
- Recent reported sale price and transaction date for comparable apartment units.
- Comparison with the highest normal sale price in the selected lookback period and a recovery-rate indicator.
- Recent jeonse deposit, jeonse-to-sale ratio, monthly-rent conditions, and rental transaction volume when available.
- Estimated monthly principal-and-interest payment under the user's financing assumptions.
- Funding-gap and effective-LTV context when a candidate does not fit the entered cash and loan assumptions.
- K-APT management-cost context where a complex can be matched to the relevant public apartment-management data.
- Reference map locations for leading candidates so results can be understood geographically.
Methodology
How the comparison is built
Start with reported transactions
APT uses reported transaction records rather than current listing advertisements as the market baseline. Sale, jeonse, and monthly-rent records are grouped around the same complex, location, and similar exclusive area so the comparison is based on completed transactions rather than asking prices.
Separate market evidence from financing assumptions
Transaction prices come from public records. Loan amount, interest rate, repayment period, and available cash are user assumptions. Keeping those two layers separate makes it easier to see whether a result changed because the market data changed or because the user's financing assumptions changed.
Translate purchase price into a monthly burden
For purchase scenarios, the service estimates an equal-payment principal-and-interest schedule from the entered loan amount, annual rate, and term. The result is a planning estimate, not a bank quote, and it excludes lender-specific underwriting, fees, and household-specific credit conditions.
Add rental and management-cost context
Recent jeonse and monthly-rent records provide an alternative to the purchase scenario. Where a K-APT complex match is available, public management-cost data is used as additional recurring-cost context. Management charges can vary by household usage and billing rules, so they are presented as estimates rather than guaranteed bills.
Limits
What the result does not prove
- Reported transactions are historical records and are not a list of homes currently available for sale or rent.
- Public records can be revised, delayed, cancelled, or unavailable for a particular period or complex.
- Mortgage calculations are scenarios only and do not represent loan approval, a lender quote, or financial advice.
- Management costs vary by household consumption, season, unit characteristics, and the complex's allocation rules.
- The internal ranking score is a comparison aid, not an investment-return forecast or recommendation to buy a particular property.
Data sources
Where the public-data context comes from
FAQ
Questions worth answering before using the result
Does APT show apartments that are currently for sale?
No. APT analyzes reported transactions and financing scenarios. It is not a real-estate listing marketplace and does not claim that a displayed apartment is currently available.
Why compare both purchase and rental records?
A purchase price is easier to interpret when recent jeonse and monthly-rent alternatives are visible beside it. The goal is not to declare one tenure type better, but to make the trade-off easier to inspect.
Is the monthly mortgage payment exact?
No. It is a scenario based on the entered rate, term, LTV, and cash assumptions. Actual financing depends on lender rules, borrower eligibility, fees, product type, and the final loan contract.
Why can management-cost estimates differ from a real bill?
Complex-level public management data cannot reproduce every household's consumption. Electricity, water, heating, seasonality, occupancy, and allocation rules can all change the amount charged to one unit.
What is the most useful way to use the score?
Treat it as a sorting aid. Open the underlying transaction, financing, rental, and cost fields before making any housing decision.
Live workspace
Use the documented assumptions in the actual APT tool.
This page explains the scope and methodology. The interactive calculation runs on apt.tooolbox.com.