Well-being equations are often estimated to generate monetary values for non-marketed activities. In such studies, utility is often approximated by either life satisfaction or General Health Questionnaire scores. We estimate and compare monetary valuations of informal care for the first time in the UK employing both measures, using longitudinal data on well-being and informal care provision. The choice of well-being measure has some effect on the estimated parameters and resulting monetary valuations, but any differences are not statistically significant. Further research is needed to confirm the comparability of these measures if researchers are to continue to use them interchangeably.