APT · SIDE-BY-SIDE COMPARISON · NOTE 02

How 3.5% versus 5.0% changes the same loan

A rate sensitivity check for a fixed ₩480M principal and 30-year equal-payment schedule.

INPUT AND EVIDENCE LEDGER

Put the two cases on the same footing.

FieldValueOrigin
Loan principal₩480,000,000Held constant
Term30 years / 360 paymentsHeld constant
Lower-rate case3.5%Illustrative assumption
Higher-rate case5.0%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.

CheckFormula or ruleResult
3.5% paymentStandard equal-payment formulaAbout ₩2,155,415 per month
5.0% paymentSame principal and termAbout ₩2,576,744 per month
Monthly difference₩2,576,744 − ₩2,155,415About ₩421,329
First-year cash difference₩421,329 × 12About ₩5,055,948

SOURCE SNAPSHOT

The official values behind the comparison.

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.

OWNER AUTHORIZATION + VERIFICATION RECORD

One accountable operator and a reproducible check record.

The TOOOLBOX site owner authorized this publication scope and remains the correction contact. The checks below were completed during preparation with AI-assisted implementation; they are an audit record, not a claim of licensed professional review.

Review ID
TB-APT-02-20260902
Owner role
TOOOLBOX site owner and developer
Release scope
Owner-authorized · 2026-09-02
Correction channel
Public contact page
  1. Recomputed every displayed result from the declared inputs.
  2. Opened each linked official source and verified the limited role it supports.
  3. Read the final page for claims that extend beyond the evidence or calculation.

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

Compare another evidence pattern.

The related notes deliberately use different questions, data states, and editorial forms.

13 · A cancelled transaction must leave the price baseline14 · Normalize area before comparing two sale records