The document offers guidance on the selection of an appropriate method(s) to measure the flow properties of powders for powder feedstock based additive manufacturing processes. This document offers several definitions and parameters that affect powder flowability, in addition to several references for additional definitions and parameters. It is intended that the guidance provided in this document not only applies to the virgin condition of the powder but also the used powder as a result of any number of successive builds. It is well known that the physical behaviour of the powder is also affected by the manufacturing process itself during the recovery and sieving cycles of the powder during the production processes. This condition of the powder going back into the system can be called out and monitored from successive builds to detect any drift of the powder properties. This document applies to: the conditions that have an influence on flow properties, and the necessary information in a test report. This document is aimed for test equipment manufacturers, material suppliers, additive machine manufacturers, and additive manufacturing machine users.