What is Sozialversicherung?
In Germany, social insurance (Sozialversicherung) has five branches: pension, health, long-term care, unemployment and accident insurance (the latter is paid by the employer alone). Contributions are calculated on gross wages.
Employees and employers generally split the contributions in half, up to the annual contribution ceilings (Beitragsbemessungsgrenzen). The employer withholds the employee's share from wages and pays everything over.
In practice
Around 20% of gross wages goes to social insurance as the employee's share: roughly 9.3% pension, ~8.55% health, 1.8% long-term care and 1.3% unemployment insurance.