The theoretical contract (or monthly pay system) is the principle that ensures your employees receive the same salary each month, regardless of the month’s length (29, 30 or 31 days).
It is based on an average (52 weeks / 12 months = 4.3333 weeks per month) and is indicative. It cannot be used to calculate overtime, additional hours beyond the contract, or missing hours.
How it is calculated
Multiply the employee’s weekly working time by 4.3333.
🔎 For a contract with 35 hours/week:
35 × 4.3333 = 151.67 h/month (i.e. 151h 40)
Why actual hours differ
A month rarely contains exactly 4.3333 weeks.
➡️ The hours actually worked therefore vary from one month to another.
➡️ The theoretical contract remains fixed and ensures a stable salary.