汽车贷款计算器指南：月供是如何计算的
An auto loan turns the price of a car into equal monthly payments over a fixed term — usually 36 to 72 months. The math is the same amortization formula as any installment loan, but two car-specific twists make auto loans especially tricky: depreciation (the car loses value faster than you pay down the loan) and APR vs. interest rate (fees get folded in).
The Monthly Payment Formula
- M — monthly payment
- P — amount financed (price − down payment − trade-in)
- r — monthly rate (APR ÷ 12)
- n — total months (years × 12)
Example: a $30,000 car, $4,000 down, 6% APR for 60 months. P = $26,000, r = 0.005, n = 60. M = 26,000 × [0.005(1.005)60] / [(1.005)60 − 1] ≈ $503/month. Total paid: $503 × 60 = $30,180, so interest ≈ $4,180.
APR vs. Interest Rate
The interest rate is the cost of borrowing; the APR (Annual Percentage Rate) bundles in loan fees, so APR is always ≥ interest rate. Always compare loans by APR — it's the true annual cost.
Longer terms drop the payment sharply, but cars depreciate ~20% in year one and 60% over 5 years. A 72-month loan can leave you "underwater" — owing more than the car is worth — for years. That's disastrous if the car is totaled or you want to sell.
Depreciation Outpaces Principal
In the early years of a loan, the car's value falls faster than your balance drops. On a $30K car financed over 72 months, by month 24 you might owe $22,000 on a car worth $19,000. Gap insurance covers this difference if the car is totaled — strongly recommended for long loans or small down payments.
How to Pay Less
- Put 20% down. Avoids negative equity and lowers every payment.
- Keep the term ≤ 60 months. Saves thousands in interest and prevents being underwater.
- Compare dealer vs. bank vs. credit union. Credit unions often beat dealer rates.
- Don't finance taxes & fees. Pay them upfront if you can.
Put It Into Practice
Enter the car price, down payment, trade-in, APR, and term to see your monthly payment, total interest, and an amortization schedule.
auto loan 将汽车价格在固定期限内（通常为 36 至 72 个月）转化为等额月供。其数学原理与其他分期贷款的 amortization 公式相同，但汽车贷款有两个特殊之处使其格外棘手：depreciation（汽车贬值速度快于你的还款速度）和 APR vs. interest rate（费用被计入其中）。
月供计算公式
- M — 月供
- P — 融资金额（车价 − down payment − trade-in）
- r — 月利率（APR ÷ 12）
- n — 总月数（年数 × 12）
例如：一辆 $30,000 的汽车，$4,000 首付，6% APR，期限 60 个月。P = $26,000，r = 0.005，n = 60。M = 26,000 × [0.005(1.005)60] / [(1.005)60 − 1] ≈ $503/月。总还款：$503 × 60 = $30,180，因此 interest ≈ $4,180。
APR 与 Interest Rate 的区别
interest rate 是借款成本；APR（年化百分率）将贷款费用计入其中，因此 APR 始终 ≥ interest rate。务必以 APR 为基准比较贷款——它才是真正的年度成本。
更长的期限会大幅降低月供，但汽车在第一年贬值约 20%，5 年内贬值 60%。72 个月的贷款可能让你多年处于"资不抵债"的状态——欠款超过汽车的实际价值。如果汽车被认定为全损或你想出售，这将是灾难性的。
Depreciation 速度超过 Principal
在贷款的前几年，汽车价值的下降速度快于你的余额减少速度。对于一辆 $30K 的汽车，贷款期限 72 个月，到第 24 个月时，你可能欠 $22,000，而汽车仅值 $19,000。如果汽车被认定为全损，Gap insurance（差额保险）可以弥补这一差额——强烈建议长期贷款或低首付的用户购买。
如何减少支出
- 首付 20%。避免负资产并降低每笔月供。
- 期限控制在 ≤ 60 个月。节省数千 interest 并防止资不抵债。
- 比较经销商、银行和信用合作社的报价。信用合作社的利率通常低于经销商。
- 不要将税费和费用纳入融资。如有能力，请 upfront 支付。
付诸实践
输入车价、down payment、trade-in、APR 和期限，即可查看月供、总 interest 和 amortization 计划表。