The computer program WPACKING was validated using bin data for three different bin conditions: 1) a smooth-walled bin filled with wheat, 2) a corrugated-walled bin filled with wheat, and 3) a corrugated-walled bin filled with corn. WPACKING is a computer program which utilizes the differential form of Janssen’s equation to predict the pressures and amount of material stored in a bin. The differential form of Janssen’s equation allows the material properties in the equation to vary as a function of different properties. The material properties suggested for use in the WPACKING program were based upon previous experimental work by various researchers. From using the WPACKING program, it was apparent that a change in grain height has a greater effect in increasing the amount of packing than does a change in bin diameter or moisture content of the stored material.