We present our calculation results for organic magnetic electrides. In order to identify the "cavity" electrons, we use maximally localized Wannier functions and the "empty atom" technique. The estimation of magnetic coupling is then performed based on magnetic force linear response theory. Both short- and long-range magnetic interactions are calculated with a single self-consistent calculation of a primitive cell. With this scheme we investigate four different organic electrides whose magnetic properties have been partly unknown or under debate. Our calculation results unveil the nature of magnetic moment and their interactions, and justify or defy the validity of preassumed spin models. Our work not only provides useful insight to understand magnetic electrides but also suggests a paradigm to study the related materials.