Rating uses two axes: housing-cost ratio (after-tax basis) × monthly surplus. ◎ Safe <30% / ○ Sound 30–40% (or 40–50% with ample surplus) / △ Caution / × Reconsider
Social insurance is an estimate (Kyokai Kenpo Tokyo health insurance, employee pension, employment insurance, long-term care for age 40+). Bonus portions apply the standard-bonus caps (health ¥5.73M/yr, pension ¥1.5M/payment).
Income tax includes the special reconstruction surtax (base income tax × 2.1%). Residential tax is the 10% income levy plus a ¥5,000 per-capita levy.
The income-adjustment deduction (cap ¥150k) applies when income exceeds ¥8.5M with a dependent under 23 (approximated as dependents ≥ 1).
The spousal deduction applies only when the spouse meets the income requirement; in dual-income / pair-loan mode it is automatically excluded.
Mortgage tax credit: 0.7% of year-end balance; the portion not offset against income tax is credited against residential tax up to ¥97,500. Excluded if total income exceeds ¥20M.
The basic deduction phases out above ¥24M total income. The spousal deduction is excluded above ¥10M total income.
Post-retirement income is entered directly as after-tax monthly take-home (combine pension, severance, asset drawdown, etc.).
The deferred-lump-sum option approximates SBI Sumishin Net Bank's "deferred-lump-sum hybrid mortgage" (modeled with appraised value ≈ property price). The lump sum at term end must be settled via sale, refinancing, or own funds.
The 1.25× payment-cap rule is not modeled. Living costs assume 1.5% annual inflation (education & car costs are flat). This is an approximate simulation.
© Edo Partners K.K.