The annual rate is not the actual return
The annual rate is an interest rate expressed over one year. For a term shorter than a year, the actual return is scaled by the term and the actual number of days.
Time deposits · interest estimate
Fixed deposit calculator
An annual rate is expressed over a whole year. Enter the principal, annual rate and term, and the tool converts them by the actual number of days into estimated interest, actual return and the maturity amount.
Simple interest on actual days
- Inputs
- Principal, annual rate and term
- Results
- Estimated interest, actual return and maturity amount, updated as you type
The tool does not load or recommend any bank products; your data stay on your device.
01
Enter deposit details
Enter deposit details
02Live result
Estimated amount back at maturity
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Including estimated interest of —
The calculation runs in your browser; the principal and rate are not stored.
How was this result calculated?
Principal × annual rate × actual days ÷ days in the year
The tool estimates simple interest on the actual number of days from the start date to the maturity date. By default, days in different calendar years are converted at 365 or 366 days; you can switch to a fixed 365-day year. Banks differ on the interest start date, maturity date and day-count basis, and not every bank uses the same method, so follow your bank’s terms.
Data explained
After calculating,
what else to look out for?
Higher interest may mean locking money in for longer
When choosing a term, look at the maturity date and how many days the money is locked in as well as the estimated interest, and consider whether you need the money to stay available.
Early withdrawal terms are set by the bank
Banks may cut the interest or charge a fee. This tool only calculates holding the deposit to maturity and does not estimate early withdrawal.
Deposit protection is counted per bank
Protection under the Hong Kong Deposit Protection Scheme adds together the same depositor’s eligible deposits at the same member bank.
See the Hong Kong Deposit Protection Board’s informationFAQ
Time deposit interest:
common questions
How much interest does HK$100,000 earn on a three-month time deposit?
For example, at 3.4% a year starting on 4 January 2027, the deposit runs for 90 days, with estimated interest of about HK$838.36 and about HK$100,838.36 back at maturity. A “three-month” deposit is usually 89 to 92 days, depending on the start date and leap years; starting on 1 February 2027, for example, gives only 89 days, and the interest differs by a few dollars.
Why does 3.4% a year earn only about 0.84% over three months?
An annual rate expresses the interest rate over a whole year. Three months is only about a quarter of a year, and the actual return = interest ÷ principal, which is 0.84% in the example above. The “actual return” in the result is this ratio, not another annual rate.
Is a year counted as 365 or 366 days?
Public information from HSBC, Hang Seng and Standard Chartered says that Hong Kong dollar deposits earn interest on a 365-day year (366 days in a leap year), while many foreign currencies such as US dollars use 360 days. For a three-month deposit starting on 1 December 2027, the default method gives HK$846.14 and a fixed 365-day year gives HK$847.67. This tool has no 360-day option; for a deposit that earns interest on a 360-day year, the actual interest will be slightly higher than the tool’s result.
How should I compare two time deposit offers?
With the same term, simply compare the annual rates. With different terms, look at both the interest and how many days the money is locked in: in the example above, three months at 3.4% earns HK$838.36; six months at 3% from the same day earns more, HK$1,487.67, but locks the money in for 181 days, and the rate for renewing after three months is unknown. The example rates are for illustration only and are not any bank’s current offer.
Sources and notes
The calculation is done on your device; your input is not uploaded or stored. The tool does not load or recommend any bank products. Before opening a deposit, follow the bank’s formal product terms and the final amount it shows.
- Method
- Simple interest on actual days
- Days in a year
- Default: 365 in a common year, 366 in a leap year; fixed 365 optional
- Bank interest rates
- Entered by you
- Privacy
- Input is not uploaded or stored
- Calculation method checked
- 11 October 2026Results checked against independent day-count examples; not a bank quotation. Checked against the sources cited on the Chinese edition of this page.
References
- Hong Kong Deposit Protection Board (opens in a new tab)
- HSBC: deposit rates and day count (opens in a new tab)
- Hang Seng: deposit interest rates and day count (opens in a new tab)
- Standard Chartered: banking service terms (time deposit interest, clause 3.2) (opens in a new tab)
You enter the interest rate yourself; this tool uses no bank or official rate data.
Information and tool results are for general reference only and are not a recommendation or a basis for an individual decision; verify important matters independently. For limitation of liability, see Data use and disclaimer.
Coverage and limitations
Results do not include compound interest, promotional rewards, foreign exchange rates, early withdrawal charges or tax.
See worked examples (2 rows)
Simple interest on actual days; the start date counts and the maturity date does not, and days in different years are split at 365 or 366 days a year (the tool’s default method). Some banks use a fixed 365-day year, which gives slightly different results. Fees are not included and this is not a bank product quotation; the bank’s terms apply.
| Start date | Maturity date | Days | Interest | Principal plus interest |
|---|---|---|---|---|
| 2026-09-01 | 2026-12-01 | 91 | HK$747.95 | HK$100747.95 |
| 2027-12-01 | 2028-03-01 | 91 | HK$746.60 | HK$100746.60 |
Method and calculations
Banks may use different day-count bases, cut-off times and maturity date handling. Public information from HSBC, Hang Seng and Standard Chartered says Hong Kong dollar deposits earn interest on a 365-day year (366 in a leap year) and some foreign currencies on 360 days; across a leap year, a bank’s way of splitting the days may differ from the tool’s default. The tool also offers a fixed 365-day option but no 360-day option.
Published: Page content updated: