Deferred Payment Loan Calculator
From principal, rate, term and a deferral (grace) period, compute the new balance after interest capitalisation and the post-deferral monthly payment.
輸入資料
計算結果
重點速覽：Deferred (grace) loan: during deferral, interest still accrues and is usually capitalised (added to principal). Accrued = principal x rate x deferral months/12; new balance = principal + accrued; post-deferral monthly = amortised instalment on new balance over remaining term. Example: 100k at 6%, 10y, defer 12mo → accrued ≈6k, new balance ≈106k, payment ≈1,251 (from ≈1,110), total interest ≈50,165 (from ≈33,225). Deferring postpones and compounds interest. WARNING: Assumes capitalisation; some lenders allow interest-only to avoid it; real terms (daily accrual, fees) vary. Education, not advice.
計算公式
每月利率 r = 年利率 ÷ 100 ÷ 12。
延遲期後新餘額 = 貸款額 × (1 + r)^延遲月數 (利息資本化)。
延遲期累積利息 = 新餘額 − 原貸款額。
延遲後月供 = 以新餘額按原還款年期計算的等額本息供款;總利息 = 月供 × 總月數 − 原貸款額。
$$r = \dfrac{\text{年利率}\%}{12}$$$$\text{延遲後新餘額} = P \times (1+r)^{\text{延遲月數}}$$$$\text{延遲後月供} = \text{新餘額} \times \dfrac{r(1+r)^n}{(1+r)^n - 1},\quad n = \text{年期}\times 12$$使用說明
- Enter the principal, annual rate and term.
- Enter the deferral (grace) months.
- View accrued interest, new balance, post-deferral payment and total interest.
以貸款 100,000、年利率 6%、還款 10 年為例，不同延遲月數下的累計利息、延遲後月供與總利息 (HK$)。
| 延遲月數 | 延遲後新餘額 | 延遲後月供 | 總利息 |
|---|---|---|---|
| 0 個月 | 100,000 | 1,110 | 33,225 |
| 6 個月 | 103,038 | 1,144 | 37,272 |
| 12 個月 | 106,168 | 1,179 | 41,442 |
| 24 個月 | 112,716 | 1,251 | 50,165 |
理財情境案例
案例一：延遲期「只付息」vs「利息資本化」
周先生貸款 200,000、年利率 7%、還款 10 年，因周轉困難想延遲 12 個月。他有兩個選擇：延遲期完全不付 (利息資本化)，或延遲期每月只付利息。
利息資本化：12 個月累計利息約 14,458，新餘額升至約 214,458，之後月供約 2,490，總利息約 98,805。延遲期只付息：每月付息約 1,167 (200,000 × 7% ÷ 12)，12 個月共付約 14,000，本金維持 200,000，之後月供仍是約 2,322。
兩者延遲期都付出約 1.4 萬利息，但「只付息」保住本金不被滾大，之後月供 (2,322) 明顯低於資本化的 2,490。若現金流許可，延遲期內至少付息，是把延遲代價降到最低的關鍵。
案例二：延遲 24 個月，總利息多付逾 1.6 萬
同一筆貸款 100,000、6%、10 年，比較「不延遲」與「延遲 24 個月 (利息資本化)」。
不延遲：月供約 1,110，總利息約 33,225；延遲 24 個月：新餘額約 112,716，月供約 1,251，總利息約 50,165。
延遲兩年雖能在最艱難時暫緩供款，但月供反而增加、總利息多付約 16,940。延遲還款是短期救急工具，不是省錢方法 —— 用之前先算清這筆「延後的代價」。
常見問題
What is a deferred payment loan?
A loan where you postpone payments for a set grace period (student loans, renovation loans, payment holidays). Crucially, interest usually still accrues and is added to the principal (capitalised), so the balance grows even though you pay nothing.
What is interest capitalisation?
Capitalisation means accrued interest is added to the principal; future interest is then charged on that larger balance — interest on interest. It is why deferring raises both the later payment and total cost.
How much extra does deferring cost?
In the example, deferring 24 months on a 100k/6%/10y loan raises the balance from 100k to ~112.7k, the payment from ~1,110 to ~1,251, and total interest from ~33.2k to ~50.2k — about HK$17k more. The longer the deferral, the larger the penalty. Deferral is emergency relief, not a saving.
Can I avoid capitalisation during deferral?
Sometimes. Some lenders let you pay interest only during the grace period, keeping principal intact (no capitalisation). If cash flow allows, paying at least the interest during deferral is the cheapest option. Always check the lender's exact terms.
Why does my result differ from the lender?
This model uses monthly accrual and capitalisation with a fixed rate. Real loans may use daily accrual, flat (平息) vs APR, plus arrangement/fees and early-repayment charges. Treat it as an estimate; the lender's schedule is final. For Hong Kong mortgages and instalment loans, confirm the bank's deferral/clarity terms with the HKMA-regulated lender.
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。