Mobile Plan Comparison Calculator
Compare two mobile plans' total contract cost and monthly average to find the cheaper one.
輸入資料
計算結果
重點速覽：Mobile plans often bundle a handset subsidy with the monthly fee, so a low monthly fee is not automatically cheaper. This calculator sums each plan's upfront cost (handset/activation) plus monthly fee x contract months to give the total contract cost and monthly average, for a fair comparison over the same period. total cost = upfront + monthly x months. Example: A = 2,000 + 300 x 24 = 9,200; B ('free phone', 0 + 400 x 24) = 9,600 → A saves HK$400. The 'free phone' hides the handset in the higher monthly fee. WARNING: Same contract length; longer contracts mean less flexibility and early-exit penalties; also weigh data, coverage, service. Education, not advice.
計算公式
計劃總成本 = 前期費用 + 每月月費 × 合約月數。
每月平均成本 = 總成本 ÷ 合約月數。
可省金額 = |計劃 A 總成本 − 計劃 B 總成本|。
$$Total\ Cost = Upfront + Monthly\ Fee \times Months$$$$Cost/Month = \dfrac{Total\ Cost}{Months}$$使用說明
- Enter Plan A's upfront and monthly fee.
- Enter Plan B's upfront and monthly fee.
- Set the contract months to compare totals and the difference.
計劃 A (前期 HK$2,000、月費 HK$300) 對比計劃 B (前期 HK$0、月費 HK$400) 在不同合約月數下的總成本
| 合約月數 | A 總成本 (HK$) | B 總成本 (HK$) | 較便宜計劃 (省) |
|---|---|---|---|
| 12 個月 | 5,600 | 4,800 | B (省 800) |
| 24 個月 | 9,200 | 9,600 | A (省 400) |
| 36 個月 | 12,800 | 14,400 | A (省 1,600) |
理財情境案例
案例一：拆穿「免費送機」的真相
計劃 A 需付機價 HK$2,000、月費 HK$300;計劃 B「免費送機」(前期 HK$0) 但月費 HK$400。合約期均為 24 個月。
A 總成本 = 2,000 + 300 × 24 = HK$9,200;B 總成本 = 0 + 400 × 24 = HK$9,600;A 較 B 省 HK$400。
雖然 B 標榜「免費送機」、前期零負擔更吸引，但它每月多付的 HK$100 在 24 個月累積達 HK$2,400，遠超 A 一次性付的 HK$2,000 機價。手機成本其實藏在較高的月費裡 —— 加總比較總成本才能看穿真相。
案例二：合約期改變勝負
計劃 A：機價 HK$3,000、月費 HK$250;計劃 B：前期 HK$0、月費 HK$420。
24 個月下：A 總成本 = 3,000 + 250 × 24 = HK$9,000 (每月平均 HK$375);B 總成本 = 420 × 24 = HK$10,080 (每月 HK$420);A 較 B 省 HK$1,080。
本例 A 前期更高但月費更低，合約期越長越有利：24 個月 A 已明顯較省。惟須提醒 —— 較長合約雖攤薄前期成本，卻犧牲靈活性，若中途轉台可能有解約罰款，選擇時應在省錢與彈性間權衡。
常見問題
Why compare total contract cost, not monthly fee?
A low monthly plan often charges a higher handset price or activation fee, while a high monthly plan may 'give the phone free'. Only summing upfront plus the full contract's monthly fees reveals the true cost of ownership and compares plans fairly.
Can I compare if the contract lengths differ?
This calculator assumes equal contract lengths. If they differ, compare on monthly average cost instead, and note that a longer contract has less flexibility and may carry an early-termination penalty.
What else should I consider?
Beyond price: data allowance, call/SMS quotas, network coverage and speed, roaming, add-on services and customer service. Cheapest is not always best — match the plan to your actual usage.
Is a 'free phone' plan really free?
Almost never — the handset cost is usually recovered through a higher monthly fee or a longer contract, which is exactly what this calculator reveals. With the defaults (A: HK$2,000 upfront, HK$300/m; B: free phone, HK$0 upfront, HK$400/m), over 24 months A = HK$9,200 and B = HK$9,600 — A ends up HK$400 cheaper, because B's extra HK$100/month over 24 months (HK$2,400) far exceeds A's one-off HK$2,000 handset. So the 'free' handset is hidden in the monthly fee; the longer the contract, the bigger this hidden cost. Always sum upfront and full-term fees, not the 'free' label.
Is a longer contract always cheaper? What are the traps?
Not necessarily. Arithmetically, a plan with high upfront and low monthly (like A) benefits from a longer term that spreads the upfront, lowering the monthly average — e.g. vs B, A is cheaper at 12m (B saves 800), breaks even around 24m (A saves 400), and at 36m A saves 1,600. But 'cheaper on paper' is not 'better overall': early-termination penalties (exiting mid-contract can mean paying remaining months or a fee), being locked into an outdated plan (the telecom market changes fast), and an ageing phone you keep paying for. Weigh spreading the upfront against keeping flexibility, not just the lowest total.
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。