This study investigated the feasibility, validity and reliability of the Carer Quality of Life (CarerQol) instrument among informal carers of long-term care users. CarerQol-VAS measured the impact of informal care by assessing happiness, and CarerQol-7D described burden dimensions. Participants included 100 informal carers of patients obtaining day care or living in a long-term care facility in the Netherlands. Construct validity assessed the extent to which differences in background characteristics were reflected in happiness scores with univariate and multivariate statistics. Intraclass Correlation Coefficients were used to assess reliability. Results indicated that CarerQol-VAS was positively associated with caregivers’ age and health, and negatively with SRB score. The percentage of complete agreement of CarerQol-VAS between the measure moments was 60% and between 76% and 96% for CarerQol-7D. κ value and ICC of CarerQol-VAS were 0.52 and 0.86, and ranged between 0.55 and 0.94 for CarerQol-7D. Conclusion: The CarerQol measures the impact of informal care among carers of LTC users in a feasible, valid and reliable way.