The paper presents the basis of a project recently funded by FORMAS, Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning. Although there is consensus among planners and politicians that dense and compact cities are better for the environment than sprawling urban landscapes, much of what is currently being built is characterised by low urban density, ‘sprawl’. Generally researchers agree that ‘sprawl’ in industrialised countries is driven by rising average income and decreasing transport costs. Urban households can afford to demand larger dwelling units as well as daily travel long dis-tances. Individual decisions are aggregated into a force that governs the development towards ’sprawl’. The aim of the project is to analyse how urban environments can offer desired qualities, by studying households’ actual use and valuation of opportunities for work, service, leisure ac-tivities, culture and education within areas of different urban density. The contribution of the study will be a deeper understanding of what urban density means in the daily life of house-holds. The study will employ theories and concepts from planning research and environmental psy-chology. Urban density is a key concept. Range and variety of urban functions are then impor-tant additions to measurement of physical densities. Another key concept is ‘affordance‘. ’Affordance’ is here a quality or asset within a specific environment, which can be perceived and used by an individual for carrying out a certain activity. The main study is a survey covering around 2000 households within the Stockholm area. Four areas will be chosen, and around 500 households in each, admitting control for socio-economic subgroups. Study areas will be selected to illustrate different urban densities and structure, from inner city to garden suburb. The survey will cover blocks of questions con-cerning the most important affordances inherent in the actual environment of the household, such as place of work, shops, schools and social networks. The questions will be constructed to grade perceived, potential, shaped and utilised affordances in their environment. The concept of ’affordance’ will be tested as a tool for structured comparisons between urban areas regarding different aspects of density. The availability of affordances in different urban structures will be described and relationships between density, in all its aspects, and life styles can be tested.