This paper develops a formal approach to evaluating freedom in interactive settings based on the literatures on preference for flexibility and measurement of diversity. The approach posits that freedom has an instrumental component–grounded in preferences– and an intrinsic component. The philosophical justification and implications of the approach are considered. In particular, I discuss the nature of the required value judgments. Potential conflicts between freedom and efficiency are explored. On a technical level, the paper extends the notion of a diversity measure (Nehring and Puppe 2002) to menus of lotteries, which is what is needed to evaluate freedom when many agents seek flexibility simultaneously.