HomeCalcPro — 專案計算詳細報告
Tool: 購車預算與還款能力計算機 — 免費線上計算機 | HomeCalcPro | 列印時間:
購車預算與還款能力計算機 — 免費線上計算機 | HomeCalcPro
購車預算與還款能力計算機精準試算，提供行業標準公式與即時測算結果。
Monthly Income & Down Payment
Automotive 20/4/10 Affordability Guideline
Transparent mathematical methodology explained in plain English.
Max Monthly Auto Expense = Monthly Take-Home × 10% | Max Loan = PV(Rate/12, 48, Max Monthly Payment - Insurance/Gas)Applies the 20/4/10 rule: 20% down payment, 4-year (48-month) maximum loan term, and total vehicle operating costs (loan + insurance + gas) capped at 10% of gross monthly income.
Variables Explained:
- Monthly Take-Home Pay: Net after-tax monthly income.
- Down Payment & Trade-In: Cash down plus equity from existing vehicle trade-in.
- Interest Rate (APR): Auto loan financing rate (default 6.5%).
- Insurance & Fuel Buffer: Estimated monthly vehicle insurance and fuel expense.
$5,500 Monthly Net Income with $5,000 Down Payment
Determining safe maximum vehicle purchase price under conservative guidelines.
- Calculate Max Financed Amount: Present Value of $440/month at 6.5% for 48 months = $18,650.
- Add Down Payment: $18,650 + $5,000 = $23,650.
- Adjust for 8% sales tax & doc fees: $23,650 / 1.08 = $21,900 sticker price.
常見問題解答 (FAQ): 購車預算與還款能力計算機
Click any question below to expand quick answers, formulas, and expert tips.
What is the 20/4/10 rule for buying a car?
The 20/4/10 rule recommends putting down at least 20% in cash, financing the vehicle for no longer than 4 years (48 months), and keeping total monthly transportation costs (loan, insurance, gas, maintenance) under 10% of gross income.
Why should I avoid 72-month or 84-month auto loans?
While long loan terms reduce monthly payments, they cause you to pay significantly more in total interest and increase the risk of being "underwater" (owing more on the loan than the car is worth as it depreciates).