can I still use seniority or experience to explain pay differences

Experience and seniority remain valid criteria

Yes, experience and seniority may still be used to explain a pay difference. Article 4 of Directive (EU) 2023/970 requires employers to base remuneration on criteria that do not involve direct or indirect discrimination on the basis of sex. Experience and seniority are not prohibited as such — it depends on how they are applied and whether they are applied consistently and objectively within a job or job group.

The difficulty does not lie in the criterion itself, but in how it is used. A fixed number of years of service that automatically leads to a higher salary can have an indirectly discriminatory effect if its impact differs structurally between women and men — for example because women more often have career breaks due to leave. This does not make seniority as a criterion invalid, but it means that its application must be justifiable: why does experience count here, how much, and does it apply to everyone in the same job in the same way. That is exactly what gender-neutral criteria in practice concerns: a criterion is only usable if it is consistent with the job content and does not happen to disadvantage one of the sexes.

Where this fits in the hierarchy of criteria

Article 4 of the Directive mentions remuneration criteria that must be objective and gender-neutral, without providing an exhaustive list of what is or is not permitted — experience and seniority fall within the scope available to employers, provided they can be justified against that requirement. These criteria also appear when setting up a job evaluation system: what requirements does the law impose on job evaluation describes how such a system is structured, and within that, seniority is typically one of the factors that is determined and applied per job group, not a generic increase that is independent of the job content.