Work Hours and Overtime: Why You Should Not Divide Salary by 30

(365 − 104 rest days) ÷ 12 = 21.75 paid days per month.

• Daily rate = monthly salary ÷ 21.75
• Hourly rate = daily rate ÷ 8

Example: 8,700 monthly → daily 8700 ÷ 21.75 = 400, hourly 400 ÷ 8 = 50. Using 8700 ÷ 30 = 290 understates it by about 28%.

With hourly 50 and daily 400:

• Weekday extension: 1.5×. Two extra hours → 50 × 2 × 1.5 = 150
• Rest day, no compensatory time off: 2×. Eight hours → 400 × 2 = 800
• Public holiday: 3×. Eight hours → 400 × 3 = 1,200

Note: rest-day work is usually not paid at 2× if equivalent time off is granted; public-holiday work generally cannot be swapped for time off.

Actual hours = clock-out − clock-in − unpaid breaks.

• Lunch: 9:00–18:00 with a one-hour break → 8 hours, not 9
• Overnight: 23:30 → 01:15 → (24:00−23:30) + 1:15 = 1 h 45 min
• Rounding: many employers round to 15 or 30 minutes, up or down — write the rule down and apply it consistently

Use 24-hour time to avoid AM/PM confusion; align on one time zone for distributed teams.

• Overtime base: whether the contract uses basic salary or includes bonuses and allowances changes the figure — check the contract and local rules.
• "All-in" salary: where a fixed amount of overtime is included, the included hours must be explicit; anything beyond still counts separately.
• On-call versus overtime: standby is usually an allowance, but if normal work is actually performed it may be deemed overtime.

Multipliers, paid-day counts and time-off rules vary widely by jurisdiction and contract (this article uses common mainland China practice). For disputes, payroll setup or policy design, follow local law and the employment contract, and keep complete attendance records.