Sooner or later, most small business owners pause over a payslip that looks slightly off. The salary seems fine, the contract is clear, yet the number of hours does not match what your intuition expects. This usually happens in months with a start or end date, or when comparing February with March. It is not a mistake. It is a feature of how Dutch payroll is designed to keep pay stable and compliant.
Payroll systems work with average monthly hours, not with counted workdays. Weekly hours are spread evenly across the year and converted into a fixed monthly norm. For example, a 40-hour contract translates to about 173 hours per month, a 38-hour contract to about 165, and a 36-hour contract to 156. These figures stay the same every month, regardless of how many Mondays or weekends the month contains.
When an employee does not work the full calendar month, that monthly average is prorated. Suppose someone with a 40-hour contract starts halfway through a month. Payroll does not count “so many days times so many hours.” It takes the monthly average and applies only the portion of the month covered by the contract. The result is often a number with decimals, because months are not neat blocks, and payroll does not pretend they are.
The same logic explains why February never looks “cheap” on payroll and March never looks “expensive.” Two employees on identical contracts earn the same monthly salary, even though February has fewer days. From a legal and financial point of view, that consistency is essential, especially under a CAO (collective labour agreement).
For small business owners, these examples point to a broader lesson. Payslips are built for stability, not intuition. If the hours look unfamiliar, the risk is usually not in the payroll calculation but in the expectations around it. Taking a moment to understand this system makes conversations with employees easier and reduces the urge to micromanage numbers that are, in fact, doing exactly what they should.
You do not need to calculate these figures yourself. You just need to recognise the pattern. Average hours in, proration when needed, and a steady outcome across the year. Once you see that, those odd-looking decimals stop being a problem, and start being a sign that the system is quietly doing its job.
