The circular economy (CE) has been put forward as a means to decouple economic growth from environmental degradation. CE involves a transition to circular material flows that can significantly improve resource productivity. The shift requires engagement from manufacturing industries, which must increasingly reuse, remanufacture and recycle materials as a means to eliminate waste. There is no standard means to compare the circularity of manufactured products. In this project we aim to validate an indicator that currently exists as a prototype and focuses exclusively on product- level circularity. We adopt a collaborative action-research with around 20 private and public sector organisations that can assist in the refinement of a robust, legitimate and standardisable circularity indicator that can act as a fundamental lynchpin for the transition to a CE in manufacturing industries, both in Sweden and beyond.