One way to support end users of software is to provide documentation materials such as user manuals and online Help. As not all software is equally difficult to master, documentation designers need to determine the quality and quantity of the information to be included in the user documentation. A first step towards this end would be to assess the complexity of the software from the user’s point of view. This paper suggests one approach to such an assessment, based on the idea of use complexity as a multi-dimensional construct. A consideration of width, depth and height of use complexity can help designers determine documentation requirements.