Circular Economy (CE) is gaining traction among academics and stakeholders; however, there is no unified framework on how to assess it. This paper proposes a framework that is composed of two segments. The first segment includes circular processes based on the value retention stages of products and systems on different levels. The second segment comprises circular impacts measuring the goals of the CE concerning environmental performance, economic contribution, and social impact. There are eight clusters of circular processes: redesign, reduce, use and reuse, re-sell, refurbish and remanufacture, recycle, recover and recirculate. The review shows that there is a widely spread confusion and overlap between indicators for circular processes and circular impacts. A clear differentiation of each category can significantly improve the tools and methods through which to assess CE. This work aims to provide such differentiation and the foundation for the development of a systematic and standardised CE assessment framework. This review provides relevant guidance of circularity indicators to be used at the (re)design phase of products, materials and systems, as well as the environmental, social and economic considerations that circular strategies must have.