Working during your studies

It's not forbidden, but it has consequences:

1. Your studies take a back seat.
2. In the case of a permanent and not only exceptional overtime, registration in the social security system cannot be made as "working student status" (FAQ below), but full social security will be deducted from the salary.
3. The salary can be taken into account for social benefits (this also applies to family insurance anyway)

Yes, that is possible. However, the total of the two jobs must remain below the current threshold (2024: €538). If the total is higher, both jobs lose their "mini-job" status and must be registered differently with social security (usually as "working student jobs", see FAQ below!). This also leads to income tax registration and deduction of taxes in the job with income tax class VI.
In-depth information: Income tax for dependent employees (PDF)

As a technical term in social security law, this means that deductions are limited to pension insurance. Health, long-term care and unemployment insurance are omitted, which is generally more favourable for the parties involved. However, you will then have to pay your own health insurance regardless of your job (but family insurance would still be conceivable for up to €607.50 gross: Deepening... )
In-depth study "Working student status" (PDF)

Firstly, it would be important to make a complete distinction between freelance jobs and salaried/labour jobs. The former are done by entrepreneurs, which will be taken up again below. The second leads to employment contracts that are standardised by labour law (wage level, duties, holidays, continued payment of wages, ...). In addition, there are types of social insurance for these employment relationships, which then lead to registrations with the mini-job centre or the health insurance fund. Roughly speaking, these are

1. Minijobs and short-term temporary workers in the sense of "marginal employment" (PDF)
2. Working student status (see FAQ above!)
3. Fully socially insured employment

Overview of the effects of the job formats in the respective systems

If you don't earn any money, don't own any property with rental income, don't have high interest income or other income subject to income tax, you obviously have nothing to do with the tax office. But that's not what this section is about. If you are an unmarried person without children and are only an employee and have no other income, the tax registration would be a matter for the HR department and nothing else would need to be done. However, if a lot of money has been earned in individual months, an income tax return could be filed after the end of the year to recover the tax, but this can only be clarified mathematically in the overall view of the calendar year.
In more detail: Income tax for employees (PDF)

Fee-based jobs or self-employment are a completely different matter. Here, the income tax return is mandatory (see FAQ below!).

The "simple answer" of €556 gross per month on average changes if:

1. You only work on a fee basis,
2. You receive the money for a compulsory internship or a paid thesis or
3. You have to co-finance children or your partner because they do not have sufficient income of their own.

Calculation method using an example

What happens if you earn a gross income of €700 instead of a mini-job? More work, a lot of "organisation", but no more money!

The "simple answer" is: If you have a mini-job and also a maximum of occasional jobs as a "short-term temporary help", your family insurance should not be jeopardised. It should be clear to everyone that the term "short-term temporary help" is a technical term in social insurance law and that the registration with the Minijob Centre must be based precisely on this.
More in-depth information on "Marginal employment" (PDF)

All other forms of income must be measured against a value that is adjusted each year in line with wage trends and currently stands at €505 per month (as of 2024). What counts as income and how it can be reduced by allowances is based on income tax law.
Deepening family insurance

Difficulties are only to be expected if you are in a "second degree programme", whereby a consecutive Master's degree programme is generally regarded as a continuation of an initial degree programme. A training qualification that is continued in a degree programme is not necessarily a problem either. However, if these scenarios of continued initial training do not apply, the period of gainful employment must be limited if you do not want to forfeit your entitlement to child benefit:

Time limits for second education

From the point of view of the state, you are a person with income from self-employment. As a rule, this should be registered with the tax office and leads to a compulsory tax return. There are also professions that constitute a trade and therefore have to be registered with the public order office (not so common for students). In addition, if certain profit limits are exceeded, there may be a pension insurance obligation (e.g. important in freelance pedagogical work).

In-depth study: Self-employment (PDF)