Where they differ
The dimensions along which working time rules vary, and which of them actually bite.
The Dimensions, Not the Numbers
Working time rules vary along a small, stable set of dimensions. The numbers differ everywhere; the dimensions do not, which allows comparison.
What Counts as Working Time
Two countries with the same weekly maximum can require very different totals to be counted, and a system configured in one of them will undercount in the other.
The Maximum, and Whether It Averages
The headline figure diverges less than people expect. What diverges is the period it is measured over, which is where the operational difference lives.
Rest, Which Diverges Most
Daily and weekly rest requirements vary more between neighbouring countries than the headline maxima do, and they bind more often in practice.
Night Work, Defined Locally
Both halves of night work regulation are local: when the night is, and what makes somebody a night worker. One definition everywhere misclassifies.
Breaks Within the Shift
The smallest entitlement and the one most often configured once and applied everywhere, which produces short breaks in some countries.
Public Holidays and the Working Year
The holiday table is the most obviously local piece of configuration and the one most likely to be maintained by one person in a spreadsheet.
Which Differences Actually Bite
Nine dimensions diverge and only three or four change what anybody does. Sorting them is what keeps the work finite.