Purpose – The purpose of this paper is to develop a new psychometric tool for the assessment of quality of life in adult informal carers. Design/methodology/approach – Two empirical studies are reported. Study 1 describes the psychometric development. An initial pool of 100 items was constructed and completed by 385 carers across the UK contacted through carers ' centres. Principal components analysis was then conducted. In study 2, a further 101 carers took part; all completed the scale prior to the intervention and again post-intervention, allowing the authors to test utility as a tool to assess change. Findings – Using principal components analysis with study 1 data the number of items was reduced to 40 that assessed eight domains; support for caring, caring choice, caring stress, financial implications, personal growth, sense of value, ability to care and carer satisfaction. In study 2 it was found that respondents scored higher post-intervention compared to pre-intervention. Research limitations/implications – There are many carers who are not recognised by services. Practical implications – The AC-QoL promises to be a useful addition to the armoury of psychometric tools available for use with adult carers by both practitioners and researchers in health and social care, as well as of use to carers themselves and to policy makers in determining what interventions might be funded and further developed. Originality/value – The paper shows that the AC-QoL is original because of its development from both carers and professional perspectives, breadth of coverage, multi-component structure and focus on both negative and positive outcomes.