A model is developed to describe the distribution and excretion of potassium at arbitrary times during or after intake by ingestion or injection. The movement of K is tracked in greater detail than in previous models and is described in terms of anatomical compartments rather than the hypothetical, mathematically derived pools often considered. Parameter values are derived for a typical resting healthy adult male. Because of its anatomically realistic framework, the model may be used as a point of departure for modelling the behaviour of K in various subgroups of the population under less ideal conditions.