Two people count from the same date, get different results, and each assumes the other made an error. In Hong Kong, the explanation is usually simpler: they used different counting rules.
The first question is never "what day does this land on?" It is: "does this rule count calendar days or working days?"
Quick reference: which deadlines count which way
| Deadline type | Counting method | Weekends | General Holidays |
|---|---|---|---|
| Employment notice (Cap. 57) | Calendar days | Included | Included |
| Stamp duty — 30-day deadline (Cap. 117) | Calendar days | Included | Included |
| MPF enrollment — 60-day rule (Cap. 485) | Calendar days | Included | Included |
| Conveyancing milestones | Working days | Excluded | Excluded |
| Hong Kong court deadlines (RHC/RDC Order 3) | 7 days or less: working days; longer periods: calendar days | Short periods exclude them; longer periods include them | Short periods exclude them; longer periods include them |
| Land Registry registration | Working days | Excluded | Excluded |
The pattern: the deadlines with the steepest penalties run in calendar days (no pauses, no mercy), while professional-practice deadlines tend to use working-day rules.
"One month" is not 30 days
The Employment Ordinance (Cap. 57) defines a "month" for notice periods with a precision that surprises most people:
- The month starts on the day notice is given (that day counts)
- It ends at the end of the day before the corresponding date in the following month
- Example: notice given on 13 February expires at the end of 12 March
Special cases:
- If no corresponding date exists: the month ends on the last day of the following month (e.g., 30 January → last day of February)
- If notice is given on the last day of a month: the month ends on the last day of the following month (e.g., last day of February → 31 March)
This is calendar-day counting. Weekends, General Holidays, and typhoon days are all included — the clock does not pause.
"Working day" does not have one definition
In Hong Kong conveyancing, a working day typically excludes:
- Saturdays
- Sundays
- General Holidays under Cap. 149
- Days when Tropical Cyclone Warning Signal No. 8 or above is hoisted
- Days when a Black Rainstorm Warning is in effect (before office hours)
But not every contract uses the same definition. The Law Society Conditions of Sale 2012 may define it differently from a bespoke commercial agreement. Always check the source document.
Three questions before you touch a calculator
- Does the source rule explicitly state calendar days or working days? If it says "days" without qualification, check whether there is a statutory default.
- Does the rule define which days are non-working? Some exclude only Sundays; others exclude Saturdays, General Holidays, and adverse weather days.
- Does it specify rollover behaviour? If the final day falls on a non-working day, does the deadline move to the next working day, or does it stay?
If any answer is unclear, document your assumption in writing before sharing the result.
Why smart teams still get this wrong
- Jurisdiction carry-over. UK and Singapore rules differ from Hong Kong. Templates imported from another office may silently use the wrong method.
- Mixed workflows. Internal policy deadlines may use working days while contractual deadlines use calendar days — and both appear in the same project timeline.
- Mid-stream switching. A matter that crosses employment, property, and compliance workflows may hit three different counting methods in one timeline.
- The government-deadline assumption. People assume all government deadlines exclude holidays. Stamp duty and MPF deadlines do not.
Same start date, two very different answers
Scenario: "30 days" from 1 October 2026.
| Method | Result | What happens on 1 Oct? |
|---|---|---|
| Calendar days | 31 October (Sat) | National Day is included in the count |
| Working days | Mid-November | National Day (1 Oct), Chung Yeung (19 Oct), weekends all excluded |
The gap exceeds a week. This is not a rounding error — it is a material mistake that can trigger penalties, missed filings, or contractual disputes.
Recommended workflow
- Confirm the method first. Check the governing statute, contract clause, or rule set.
- Set holiday and shutdown assumptions second. Which year's holiday list? Any extended shutdowns?
- Calculate once. Use a consistent tool or process.
- Run a sensitivity check only if the result date is near holidays, weekends, or a CNY cluster.
- Document the method in any output you share:
Method: working days | Holidays: HK 2026 | Shutdown: none.
Where the calculator helps
The HK calculator lets you switch between counting methods and see the impact immediately. You can compare a working-day count against a calendar-day count from the same start date to check sensitivity.
For calculator configuration details, see the Info Guide.
