The main objective of this article is to compare European medium-sized cities in terms of compactness. Both existing and new metrics are used. The metrics are based on the fusion of recently available European-wide data sets with common standards for all countries. The fused data used in specific are Urban Atlas and Urban Audit. One source of inspiration of new metrics is landscape ecology, but the analogies are not always straightforward. The method is applied to a large number of cities. It is found that the combination of existing metrics with those newly proposed is able to adequately describe compactness and its components. © 2014, © 2014 Taylor & Francis