What is an A1 form?

An A1 form is an official certificate that proves an employee remains covered by their home country’s social security system while temporarily working in another European Economic Area (EEA) country or Switzerland. It prevents double social security contributions, ensuring the employee and employer only pay into one system at a time.

For example, if a German employee is sent to work on a project in France for a few months, the A1 form confirms they continue paying contributions in Germany rather than also in France. Without it, companies risk unexpected costs, fines, or compliance breaches.

Employers are responsible for applying for an A1 form before the assignment begins, typically through their national social security institution.