Core answer: workdays = calendar days − weekends − public holidays + shifted working days. Of 365 days a year, roughly 250 are workdays and 115 are rest days. A 30-calendar-day project usually has only ~21 usable workdays.
The counting rules
- Standard schedule: Monday-Friday work, Saturday-Sunday off
- Statutory holidays off for everyone (table below)
- Shift system: to stitch holidays into longer breaks, adjacent weekends may become working days (per the State Council's annual notice)
Quick estimate: workdays ≈ calendar days × 5/7, minus holidays in the window.
Where does 21.75 come from?
Average monthly PAID days = (365 − 104) ÷ 12 = 261 ÷ 12 = 21.75 days
- 104 = 52 weeks × 2 weekend days
- The 11-13 statutory holidays are PAID, so they aren't subtracted
Application: daily wage = monthly salary ÷ 21.75. On a ¥10,000 salary, one day of leave deducts 10000÷21.75 ≈ ¥459.8. Overtime pay uses the same 21.75 base.
Project-duration examples
Example 1: project starts Monday, March 3, 30 calendar days to April 1:
- 30 days = 4 full weeks + 2 days → ~9 weekend days
- No holidays in the window
- Real workdays = 30 − 9 = 21 days
Example 2: a 20-day task starting September 28 (pre-National-Day):
- Spans the Oct 1-7 holiday (7 days off, shifts included)
- Of 20 calendar days: ~6 weekend days + ~4 statutory days
- Real workdays ≈ 20 − 6 − 4 = 10 days — serious schedule risk
Statutory holiday list
| Holiday | Days | Dates |
|---|---|---|
| New Year's Day | 1 | Jan 1 |
| Spring Festival | 4 | Lunar New Year's Eve to day 3 |
| Qingming | 1 | Around Apr 4-6 |
| Labor Day | 2 | May 1-2 |
| Dragon Boat | 1 | 5th day of the 5th lunar month |
| Mid-Autumn | 1 | 15th day of the 8th lunar month |
| National Day | 3 | Oct 1-3 |
13 statutory days total (Spring Festival and Labor Day each gained a day from 2025). Shifts stitch these into 8-day Spring Festival and 7-day National Day breaks.
Common mistakes
- "21.75 is the monthly workday count": it's the average PAID-days figure (holidays included), not actual workdays — real months run 20-23.
- Promising calendar-day deadlines: telling a client "30-day delivery" across Spring Festival or National Day can cut real workdays by 40%.
- Prorating overtime over 30 days: wrong — the law requires the 21.75 base, which pays ~27% more per day.
- Forgetting shifted working days: the Saturdays/Sundays around Spring Festival and National Day ARE workdays — check the year's official notice before scheduling.