In 2016, the Flemish Government set the transition to a circular economy (CE) as one of its priorities. Adopting the paradigm of circularity in, amongst others, the building sector has the potential to create more sustainable buildings, where the use of new resources and the production of waste is minimised by closing material flows. However, circular building implies radical changes at different levels: from organisational changes within the sector to new design methods. To support and guide stakeholders in this transition to a CE in the Flemish building sector, different organisations developed design support tools and methods. However, due to the lack of overview of the available tools and their purpose, it is unclear for the stakeholders which tool could fit best for their context. Therefore, this research analyses the potential of the identified tools for circular building practice. Further, the possible impact potential of the tools in a circular design process is assessed by reviewing the needs of circular building stakeholders and by comparing that need with the tools. The tools and needs are classified per building design aspect and per design stage. Subsequently, conclusions can be drawn on opportunities to develop new design support tools for circular buildings and on opportunities to improve existing tools.