INPUT AND EVIDENCE LEDGER
Put the two cases on the same footing.
| Field | Value | Origin |
|---|---|---|
| Loan principal | ₩480,000,000 | Held constant |
| Term | 30 years / 360 payments | Held constant |
| Lower-rate case | 3.5% | Illustrative assumption |
| Higher-rate case | 5.0% | Illustrative assumption |
DECISION READING
Read the gap, not just the winner.
A property can fit at one assumed rate and fail the same household budget at another. APT should therefore expose the rate as an editable assumption rather than burying it inside a score.
REPRODUCIBLE WORK
The comparison ledger.
| Check | Formula or rule | Result |
|---|---|---|
| 3.5% payment | Standard equal-payment formula | About ₩2,155,415 per month |
| 5.0% payment | Same principal and term | About ₩2,576,744 per month |
| Monthly difference | ₩2,576,744 − ₩2,155,415 | About ₩421,329 |
| First-year cash difference | ₩421,329 × 12 | About ₩5,055,948 |
SOURCE SNAPSHOT
Official context and the limited role it supports.
SENSITIVITY
Conditions that can reverse the gap.
- Shorter terms usually raise the monthly payment while reducing total interest.
- A larger cash contribution reduces both payments, but ties up more capital.
- Actual products can use different repayment structures, fees, and rate-reset rules.
HUMAN ACCOUNTABILITY + AI USE RECORD
The owner is accountable; the technical checks were AI-assisted.
The TOOOLBOX site owner authorized the publication scope and remains the correction contact. AI assistance was used for drafting, implementation, arithmetic recomputation, and source-link checks. This record does not claim line-by-line human fact-checking or licensed professional review.
- Record ID
- TB-APT-02-20260906
- Owner role
- TOOOLBOX site owner and developer
- Technical check date
- 2026-09-06
- Human fact-check
- No separate human fact-check recorded
- AI use
- Drafting, code, arithmetic, and link checks
- Correction channel
- Public contact page
- Recomputed both 360-payment schedules with the same ₩480M principal and term.
- Reconciled the ₩421,329 monthly gap to the ₩5,055,948 first-year difference.
- Verified that neither illustrative rate is described as a current offer or eligibility result.
BOUNDARIES
Claims this comparison cannot support.
- The calculation assumes a constant nominal rate for the full term.
- It excludes fees, insurance, early repayment, and lender-specific schedules.
- The two rates are scenarios, not current offers.
MORE APT DECISION NOTES
Test the result yourself.
This note preserves a dated calculation. Change the inputs in the live workspace, or compare another evidence pattern below. Live source availability and results can differ from the dated example.