The provisions of the Labour Code specify working time standards, that is: 8 hours a day and an average of 40 hours per week in an average 5‑day working week in the adopted reference period. On the basis of these standards, the employer determines the working time, that is the number of hours and days to work in the adopted working time reference period.

The number of these hours is calculated as follows:

• by multiplying 40 hours by the number of weeks per reference period, then
• by adding – to the number of hours obtained – the product of 8 hours and the number of days remaining until the end of the reference period, from Monday to Friday.

Each holiday occurring during the reference period and on a day other than Sunday reduces working time by 8 hours.

Such holidays are:

• 1 January – New Year's Day,
• 6 January – Epiphany,
• Easter Sunday and Easter Monday,
• 1 May – May Day,
• 3 May – Constitution Day,
• Pentecost Sunday,
• Corpus Christi,
• 15 August – Assumption of the Blessed Virgin Mary,
• 1 November – All Saints’ Day,
• 11 November – Independence Day,
• 25 and 26 December – Christmas Day and Boxing Day.