Cash Back Calculator
From spend and the cash-back rate, compute the cash rebate you earn; compare flat vs tiered rates and annual cap.
輸入資料
計算結果
重點速覽：Cash back = spend x rate. Many HK cards are tiered/capped: a higher rate up to a monthly cap, then a lower base rate. Compare the effective rate on your real spend. Example: HK$10,000/m at 2% = HK$200/m = HK$2,400/y. A 5% rate with a HK$300 monthly cap is only better if your spend hits the cap. WARNING: Watch annual fees, minimum spend, eligible categories, and whether rewards are points (convert at a ratio) vs straight cash. The best card matches where you spend. Education, not advice.
計算公式
回贈金額 = 消費額 × 回贈率 ÷ 100。
實際淨支出 = 消費額 − 回贈金額。
$$回贈金額：$CashBack = Spend\times\dfrac{Rate\%}{100}$$$$$實際淨支出：$NetCost = Spend - CashBack$$$$$示例：$1{,}000\times\dfrac{2\%}{100}=20$$$使用說明
- Enter your monthly spend.
- Enter the cash-back rate.
- View the monthly and yearly rebate.
不同消費金額與回贈率下的回贈與淨支出
| 消費金額 (HK$) | 回贈率 | 回贈金額 (HK$) | 實際淨支出 (HK$) |
|---|---|---|---|
| 1,000 | 2% | 20 | 980 |
| 5,000 | 1% | 50 | 4,950 |
| 10,000 | 3.5% | 350 | 9,650 |
| 2,000 | 5% | 100 | 1,900 |
理財情境案例
案例一：計算一筆簽賬的回贈與淨支出
某人用一張回贈率 2% 的信用卡簽賬消費 HK$1,000。
回贈金額 = 1,000 × 2% = HK$20；實際淨支出 = 1,000 − 20 = HK$980。
解讀：這筆消費實際只花了 HK$980，等於用信用卡付款比用現金多賺了 HK$20。對於本來就要花的支出 (如日常購物、繳費),選一張回贈較高的卡，就能積少成多地省下開支。
案例二：回贈賺的，可能還不夠付一個月利息
某人用回贈率 2% 的信用卡消費 HK$10,000，賺得回贈 = 10,000 × 2% = HK$200。但他沒有全數還款，讓 HK$10,000 結欠滾存了一個月，該卡循環年利率 (APR) 30%。
拖欠一個月的利息 ≈ 10,000 × 30% ÷ 12 = HK$250。
解讀：辛苦賺回的 HK$200 回贈，竟然還不夠付這一個月產生的 HK$250 利息——不但沒着數，反而倒蝕 HK$50。這說明追求回贈的大前提是『準時全數還款』;一旦動用循環信貸，高昂的利息會輕易吞掉所有回贈。信用卡回贈只對『每期清卡數』的人才真正划算。本計算器只計回贈本身，切勿為賺回贈而過度消費或拖欠還款。
常見問題
How is cash back calculated?
Cash back = monthly spend x rate. Example: HK$10,000 at 2% = HK$200/month, HK$2,400/year. For a tiered card, split the spend into the capped high-rate band and the base-rate band and sum them.
Why do caps matter?
A high headline rate (e.g. 5%) often applies only up to a monthly cap (e.g. HK$300), then drops to ~1%. If your spend exceeds the cap, the extra earns the base rate, so the effective rate falls. Compare the effective rate past your typical spend, not the headline.
Are rewards always cash?
No. Many cards give points/miles redeemable for cash, vouchers or travel at a conversion ratio. The real value depends on the redemption; a 'rich' points rate may be worth less than it looks. Prefer cards whose rewards you actually use at a good rate.
Should I chase the highest cash-back card?
Pick by where you spend. A card with 5% on dining beats 2% on everything only if you dine a lot. Also net out the annual fee and any minimum-spend requirement; a fee can eat the rebate. The right card matches your spending pattern, not the biggest number.
Any Hong Kong notes?
Hong Kong has many card reward schemes with categories, caps and welcome offers that change often. Read the terms (eligible merchants, cap, fee) and the IFEC's guidance on responsible card use. Cash back is a rebate, not a reason to overspend; pay in full monthly to avoid interest that wipes out the rebate. Education, not advice.
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。