Purpose: This article provides empirical validation of the Graduate Capital Model, adopted at a UK Russell Group University as a tool to analyse and support the career preparedness of both undergraduates and postgraduate students. An overview of employability capitals and how the development of these will potentially result in positive employment outcomes is explored. We describe the development of a psychometric tool "the Graduate Capital Scale" that seeks to operationalize these capitals. We then draw on data to establish the factor structure, reliability and validity of the tool. Design/methodology/approach: This paper introduces a new psychometric instrument, called the "Graduate Capital Scale"; this self-reflective tool aligns closely with the five capitals within the Graduate Capital Model (Tomlinson, 2017) and has been designed for higher education students to self-assess their confidence in transitioning to the graduate labour market. Findings: Based on a sample of 1,501 students across data collection waves, the findings from the psychometric scale show good factor reliability and validity for the constructs central to the overarching Graduate Capital Model. Within each of the component of the model, high factors loading emerged for a range of scale items, including subject-related skills, social networking, perceived job market fit and engagement with extra-curricula activities. Few gender differences emerged across the constructs. Research limitations/implications: The research was confined to a specific English university comprised of mainly academically high-achieving and higher socio-economic students. However, there is significant scope for the model and related scale tool to be applied to diverse student groups given its wholistic nature. Practical implications: The scale has considerable potential to be incorporated into careers practices and also embedded into course programmes as it aligns with a range of related learning outcomes. There is significant scope for this approach to complement a range of pedagogical and practical career interventions, including: self-reflective tools within tutorials; measures of learning gain for specific interventions such as careers coaching and mentoring; and as a personal reflective tool in careers guidance. Social implications: The approach developed through this employability tool has scope to be used for diverse graduate groups, including those with lower levels of career confidence, preparedness and insight and including those from lower socio-economic backgrounds. Originality/value: This paper has introduced and demonstrated the validity of a practical careers and employability development tool that has significant practical applicability for students, graduates and practitioners. Moreover, this scale supports a pre-existing conceptually driven model and has demonstrated a clear alignment between theory and practice in the area of graduate employability.