How much information from experience does a normal adult remember? The “functional information content” of human memory was estimated in several ways. The methods depend on measured rates of input and loss from very long‐ term memory and on analyses of the informational demands of human memory‐based performance. Estimates ranged around 109 bits. It is speculated that the flexible and creative retrieval of facts by humans is a function of a large ratio of “hardware” capacity to functional storage requirements.