We studied a method of estimating the number of contacts in a solid dosage form using thermal analysis. Ibuprofen (IB) and Ethenzamide (ET) were used as model actives. IB and ET were granulated and sieved with each other. We prepared mixtures of IB and ET using different diameter granules. The number of contacts between the samples was calculated by the expression method of Ouchiyama and Tanaka. By thermal analysis, we measured the quantity of endotherm up to 60-63 degrees C from 56 degrees C. The quantity of endotherm up to 61 degrees C from 56 degrees C was in good proportion to the number of contacts calculated by the expression.