Although people are living longer, there is no discernible pattern about the quality of life in an increasing lifespan. This restricts our capacity to predict and prepare for the consequences of population ageing. Accordingly, we propose a population ageing indicator that combines demographic and disability prevalence data through a characteristics approach and explore different scenarios to account for uncertainty in life quality projections. Our results, available for 186 countries, show that countries that rank older under conventional chronological ageing measures may rank younger under our qualitative measure. Additionally, we find substantial differences in our projections depending on different health assumptions, demonstrating the risk of using ageing indicators that make implicit assumptions about health characteristics.