AbstractEvaluating the effects of some or all academic research funding is difficult because of the many different and overlapping sources, types, and scopes. It is therefore important to identify the key aspects of research funding so that funders and others assessing its value do not overlook them. This article outlines 18 dimensions through which funding varies substantially, as well as three funding records facets. For each dimension, a list of common or possible variations is suggested. The main dimensions include the type of funder of time and equipment, any funding sharing, the proportion of costs funded, the nature of the funding, any collaborative contributions, and the amount and duration of the grant. In addition, funding can influence what is researched, how and by whom. The funding can also be recorded in different places and has different levels of connection to outputs. The many variations and the lack of a clear divide between “unfunded” and funded research, because internal funding can be implicit or unrecorded, greatly complicate assessing the value of funding quantitatively at scale. The dimensions listed here should nevertheless help funding evaluators to consider as many differences as possible and list the remainder as limitations. They also serve as suggested information to collect for those compiling funding datasets.