Direct assessment of capability to function may be useful in healthcare settings, but poses many challenges. This paper reports a first investigation of the feasibility of individuals self-reporting their capabilities and the meaning of the responses. The study was conducted in 2010, using think-aloud interviews with participants in the UK. The findings of the study suggest that the majority of participants were able to comprehend questions about their capabilities, felt able to judge their own capability wellbeing and provided responses in line with this judgement. In a number of cases, for example in relation to ‘autonomy’, participants highlighted that their capability was potentially greater than their functioning. The findings also show varying interpretations of the capability concept, with some participants finding the capability concept unintuitive in relation to specific aspects of life (in particular, ‘attachment’). The findings suggest that guiding individuals in the process of identifying their capabilities may be important in generating consistent responses to capability questions.