This guide is intended as a step towards a core method for measuring circularity in the construction sector. Such a method measures the degree of circularity, e.g. of a construction product, a building or a bridge. The intention is that the core measurement method put forward by Platform CB’23 will stimulate the transition to a circular construction economy. The guide is relevant to anyone engaged in circular construction. The core measurement method can be applied anywhere in the construction sector: in the buildings sector as well as in the civil and hydraulic engineering sector (infrastructure). All parties involved in the construction sector – including clients and contractors – can use the core measurement method. The guide is also of interest for people who work with comparable measurement methods or who work on circular policy, either in the Netherlands or internationally.