The construction and building sector must reduce its ecological footprint. However, concepts of the circular economy, which are increasingly being implemented in other economic sectors, are still insufficiently applied in the construction industry. Circular construction measures can reduce the consumption of raw materials, energy, and land, while lowering costs in the long term. The opportunities are evident: by preserving existing buildings, using secondary construction products, and considering conversion and deconstruction already in the planning and construction phases, circular economy principles can be implemented in construction. The economic potential of circular construction is often underestimated. Circular building can be economically viable in the long term, as maintenance and conversion costs are lower than in conventional construction. There are already several market players that have developed new business models to reintroduce valuable raw materials from buildings that are no longer in use back into the market. Digital tools for planning and documentation, as well as digital marketplaces, support implementation. As a result, circular construction can become a strong driver of innovation and modernization in the construction sector. At the same time, it supports the preservation of existing building stock and can revive established and forgotten practices of building culture.