The genesis of this paper is survey work undertaken for the Sustainable Development Council of the Urban Land Institute amongst developers and investors in real estate. The survey sought to draw out the relative importance of factors affecting the viability and sustainability of projects. One of the surprises thrown up by the survey was the perceived importance of liveability to both sustainability and viability. Unfortunately Liveability has a plethora of different definitions and very little research has been undertaken to qualify or measure the term at any level, let alone that of an individual development. This paper postulates a pragmatic version of liveability and seeks to quantify its impact at the development level through the definition of a liveability model based upon the economic, social and cultural needs of the occupier. The model takes as input liveability points awarded for each of the components based upon the development design, neighbourhood and macro statistics. These points are then weighted and aggregated into a liveability score for the development. The liveability score is then tested against the market to validate and calibrate the model. In this case the market is represented by a series of case studies representing the whole spectrum of liveable space, both commercial and residential.