Cities with high density and mixed use are often promoted as supporting sustainable development, but it is unclear what it is that actually needs to be made more dense to achieve the alleged benefits. The project responds to two questions: What are the urban qualities that need to be densified? Through which criteria can "density" of these qualities be assessed? Urban density is studied in Barcelona, Rotterdam and Gothenburg. In the final analysis and reflection, the obtained knowledge will be discussed in relation to the development of the Gothenburg area. The results of the work will be an effective and useful analytical framework - knowledge that can be used in the ongoing planning of the future Gothenburg.