家計・支出decision

Can I Afford This?

Stop impulsive spending. Stress-test whether a purchase fits your budget without depleting emergency cash or derailing long-term wealth.

入力パラメータ

ブラウザ内処理のみ

計算結果と分析

計算準備完了 (¥0)

Enter the purchase price and your monthly financial situation to evaluate affordability.

Affordability Verdict: Ready to Evaluate ($0)

Affordability Score100 / 100

10-Year Opportunity Cost$0If invested at 7% compound growth

Monthly Discretionary Buffer¥0

Cooling-Off PeriodReady

戦略的インサイト

主な洞察と次のアクション

Evaluates real affordability based on your disposable monthly cash flow and emergency reserves.
Calculates the 10-year compound growth opportunity cost if invested instead.
Helps eliminate impulse spending with data-driven decision scoring.

セクション1: 計算の仕組み

この計算の仕組み（わかりやすい解説）

True affordability is not simply whether your bank account has enough cash today. It checks three gates: (1) Does buying this compromise your 3-to-6 month emergency fund? (2) Are you carrying high-interest debt that demands this cash instead? (3) What is the true 10-year opportunity cost if this money compounded in an index fund at 7%?

セクション2: 数式と計算前提

アルゴリズム数式と計算根拠

計算式:

R = f(X_1, X_2, \dots, X_n) \quad \text{subject to standard actuarial bounds}

モデルの前提条件:

Assumes 7% historical annualized market return for opportunity cost comparison.
Assumes high-interest revolving credit cards (18-29% APR) are an urgent financial emergency.

セクション3: 実践的なシミュレーション

Comparative Impact Modeling

戦略的な調整によって将来の推移がどう変わるか確認してください:

戦略 A

Baseline Minimum Strategy

Making scheduled minimum payments without additional principal allocation.

Outcome: Maximum lifetime interest accrual and delayed financial freedom.

戦略 B（最適化）

Accelerated Decision Strategy

Allocating strategic monthly surplus directly to principal reduction.

Outcome: Significant interest reduction and exponential acceleration toward goals.

戦略のポイント: Even modest monthly adjustments create substantial compound savings over multi-year horizons.

セクション4: 例外・境界条件

モデルの制限事項と境界条件

While this engine calculates standard actuarial and consumer finance metrics, real-world finance introduces nuances that no automated model can fully predict:

Assumes tax rates, inflation indices, and APR rates remain static across modeled projections.
Educational estimate; not a formal underwriting commitment from lending institutions.
Excludes localized municipal surtaxes, insurance rider surcharges, or variable-rate APR triggers.

よくあるご質問

よくある質問: Can I Afford This?

What is the 48-Hour Rule?

For any non-essential purchase over $100, wait 48 hours before purchasing. In over 60% of cases, the dopamine surge fades and you realize you did not actually need the item.

What is the difference between "Can I buy this?" and "Can I afford this?"

You can buy something if you have the cash or credit card limit available. You can AFFORD something only if purchasing it has zero negative impact on your emergency reserve, debt payoff, or future retirement trajectory.