The aim of this study is to gain deeper understanding of the legal certainty in elderly care needs assessment. Prior literature has found differences in both interpretation and application of reasonable living conditions. However, there is a lack of research analysing how care managers balance legal demands, organisational guidelines and individual needs in their daily work to obtain legal certainty. To address this research gap, this study adopts a qualitative approach, drawing on previous research and conducting semi-structured interviews. By applying a qualitative content analysis, key themes were identified. The findings of this study indicate that legal certainty in elder care assessment primarily can be understood through a formal legal framework, whereas material legal certainty occurs via professional judgement in individual cases. Moreover, reasonable living standards are generally interpreted as a vague minimum standard, with variations between care managers and municipalities, driven by collegial norms and organisational structures. Finally, discrepancy in decision making were identified as a key factor undermining legal certainty in elder care.