Car Loan Interest Calculator
From the loan amount, annual rate and term, compute the equal-monthly-instalment payment and total interest.
輸入資料
計算結果
重點速覽：Car Loan Interest focuses on the loan: loan amount, annual rate, term → monthly payment and total interest by the equal-instalment (reducing-balance) annuity formula. r = rate/12, n = term x 12; payment = P x r(1+r)^n/((1+r)^n - 1); total interest = payment x n - P. Example: HK$240,000 at 5% for 5y → ~HK$4,529/month, ~HK$31,746 interest. WARNING: HK car loans are often quoted as 'flat rate' (平息); the same number can cost near double the APR — always compare on APR. This tool uses reducing-balance (APR).
計算公式
每月供款 = 貸款額 × 月利率 × (1 + 月利率)^期數 ÷ ((1 + 月利率)^期數 − 1)。
月利率 = 年利率 ÷ 12；期數 = 年期 × 12。
總利息 = 每月供款 × 期數 − 貸款額；還款總額 = 貸款額 + 總利息。
$$r = \dfrac{\text{年利率}\%}{12},\quad n = \text{年期} \times 12$$$$\text{每月供款} = P \times \dfrac{r(1+r)^n}{(1+r)^n - 1}$$$$\text{總利息} = \text{每月供款} \times n - P$$使用說明
- Enter the car-loan principal.
- Enter the annual rate and term.
- View the monthly payment, total interest and total repayment.
以車貸 240,000、還款 5 年為例，不同年利率下的每月供款與總利息 (HK$)。
| 年利率 | 每月供款 | 總利息 | 還款總額 |
|---|---|---|---|
| 4% | 4,420 | 25,198 | 265,198 |
| 5% | 4,529 | 31,746 | 271,746 |
| 6% | 4,640 | 38,392 | 278,392 |
| 8% | 4,866 | 51,980 | 291,980 |
理財情境案例
案例一：年期拉長，月供變輕但利息大增
陳先生想貸款 240,000 買車、年利率 5%，在 3 年、5 年、7 年之間猶豫。年期越長月供越輕，但代價是甚麼？
3 年期：月供約 7,193，總利息約 18,949；5 年期：月供約 4,529，總利息約 31,746；7 年期：月供約 3,392，總利息約 44,940。
由 3 年拉長至 7 年，月供從 7,193 降到 3,392、輕鬆一半，但總利息卻由 18,949 增至 44,940、多付逾兩萬。汽車是貶值資產，年期拖太長容易「車未供完已殘舊」，宜在月供負擔得起的前提下盡量選短年期。
案例二：利率 4% vs 9%，總利息相差逾一倍
同樣貸款 240,000、還款 5 年，信用良好者取得 4%，信用一般者被報 9%，兩者差多少？
4%：月供約 4,420，總利息約 25,198；9%：月供約 4,982，總利息約 58,920。
月供只差約 562，總利息卻由 25,198 暴增至 58,920、多付逾 3.3 萬。維持良好信用紀錄、多比較幾家財務機構的實際年利率 (APR)，往往比糾結首期多少更能省錢。
常見問題
Why is the payment fixed but interest falls each month?
Under equal-instalment repayment, the monthly payment is fixed but interest is charged on the remaining balance. As the balance falls, the interest portion drops and the principal portion rises, so you repay more principal later.
How much does the rate affect total interest?
Higher rate and longer term raise total interest sharply. For the same loan, 4% vs 8% can more than double the interest. Seek a lower rate or shorter term to save substantially.
Does early repayment save interest?
Yes. Interest is on the remaining balance, so repaying principal early cuts future interest. But check the contract for early-repayment penalties or fees.
What are typical Hong Kong car-loan rates, and flat rate vs APR?
HK car-loan APR varies by credit, vehicle (new/used) and lender, commonly from a few per cent to over 10%. The key trap is the quote basis: dealers/finance firms often quote a 'flat rate' (平息) — interest is charged on the ORIGINAL full principal for the whole term even as you repay. This tool uses reducing-balance (APR), where interest falls with the balance. The same headline number (e.g. 'flat 6%') can be roughly 'APR 11-12%' — nearly double. Always ask whether a quote is flat or APR, and compare on APR.
What to watch on early settlement of a HK car loan?
Under reducing-balance, early principal repayment theoretically saves interest; the earlier the better. But check (1) early-repayment penalty/fee (some charge a % of remaining interest or a fixed fee), (2) flat-rate loans may not refund interest proportionally, and (3) opportunity cost if your cash earns more elsewhere. Confirm the rate basis and penalty before settling early.
相關工具
參考資料
內容審核：香港計算器財經團隊。計算邏輯與公式參考香港金融管理局（HKMA）及投資者及理財教育委員會（IFEC）之個人理財計算指引，結果僅供參考，實際以相關機構公佈為準。