Abstract Reuse of building components is one of the recommended circular strategies to reduce the environmental impact of new buildings. However, reclaimed building components are more difficult to design with than new products. While new products can be made to match exact needs, the salvaged components have predefined dimensions and quality limitations. Following the Design Science Research methodology, we attempt to answer how the reuse design can be aided by a digital design tool. The developed matching algorithms suggest the optimal assignment of available elements for the desired configuration, considering user-defined constraints and optimisation criteria. In the test cases, we seek to optimise the global warming potential of timber framing elements, defined by life cycle assessment, though the tool is not limited to this objective. The implementation includes greedy algorithms, bipartite graphs, and mixed integer linear programming. The usefulness of the proposed solution is evaluated on simulated sets of building elements in terms of embodied emission reduction and speed of the calculation. The paper contributes with methodologies, algorithms, and test cases to assess their performance. Practitioners can apply the proposed solution to reduce the time of designing with salvaged materials, which can lead to the popularisation of the circular design.