This document proposes a method to define circular products design rules. It details principles, requirements and guidance associated with the proposed method. This document: " specifies requirements and guidance for integrating circularity into the design and development process of products by an organization. " supports organizations to develop product design rules to fulfil their chosen circular categories (e.g. the circular business models chosen by the organization or the legislation requirements). Having the life cycle thinking as a core principle, this document provides guidance on how to reduce environmental impacts, and how to deal with challenges such as trade-offs during circular product design, without compromising functions and safety. This document focusses on material efficiency. It is not a management system standard. This document can be applied when no product-specific or product group standard exist. Where such documents are developed, this document can be used as reference to ensure consistency and harmonization across the different product areas and supply chains or networks.