Capturing and measuring qualities of the built environment is a fundamental aspect of planning. Planners need to develop a vivid picture of the physical and social environments people inhabit in order to understand what impacts their plans and actions may have. Measures can indicate the built environment’s qualities and represent them in a way that is useful for planning to address particular issues and problems. One issue that is currently receiving much attention in planning is the place of children in urban and urbanising environments (Mitchell et al 2007; Handy et al 2008; Lim and Barton 2010; Giles-Corti et al 2011). Noted in this research is that the relationship children share with urban environments is distinct from that of adults in many ways. If planners are to accommodate children in their plans or design plans specifically for children, measures of urban quality and the built environment need to reflect the needs and capacities of children. This paper is based on the understanding that what planners measure, how it is measured and how measures are used to inform planning plays an integral part to contributing to healthy and safe environments for children. What goes on when we measure and how measures work, needs to be understood in order to be open to possibilities of creating better methods and practices. The purpose of the paper is to explore both the nature of built environment measures and explore their normative aspects, establishing possible avenues for improvement. It will do this by first establishing the role of and looking at a number of issues related to the use of built environment measures in planning. A detailed look at how measures are constructed will follow and ideas from planning theory will be drawn upon to suggest approaches of improving measures. The approach is based upon a review of existing built environment measures in urban planning research; literature on the nature of the human-environment relationship; and methodological discussions on measurement.