It depends on the type of marginal part-time employment and the hourly wage. In a minijob with an earnings limit, you may not earn more than €520 per month. The statutory minimum wage in Germany is €12 per hour. If you earn this, you are not allowed to work more than 43.3 hours per month. The higher your hourly wage, the fewer hours you are allowed to work per month.
With short-term employment (as offered at Zenjob), the number of hours doesn’t matter as much as the number of working days. With this type of minijob, you can work up to 70 days per calendar year. A working day is every day you work a shift, regardless of how long or short it is. If you only work 8-hour shifts, you can work up to 560 hours in total over the course of your short-term employment.
Additionally, there are some other factors to consider when it comes to working hours in a minijob. As a student from the European Union, Iceland, Liechtenstein, Norway or Switzerland, you may only work up to 20 hours per week while classes are in session (Vorlesungszeit). As a student from all other countries, you may only work 120 full days or 240 half days per year in Germany.
If you have a minijob alongside a full-time job, you must comply with the maximum working hours of 48 hours per week stipulated in the German Working Hours Act (Arbeitszeitgesetz). Please note that you can only sign up with Zenjob if you study full-time at an officially recognized university.