The authors derive simple equations for estimating the heat of combustion of raw shale by thermochemical estimates and by linear regression of experimental data. They find that the heat can be estimated well by an exothermic term that accounts for the combustion of organic matter and a constant that accounts for pyrite combustion, carbonate decomposition, and glass formation. The net contribution of reactions included in the constant is endothermic for the standard state products of bomb calorimetry. As a sample application, the authors perform an energy balance on a modified Fischer assay of average Green River shale by using one of our formulas for raw shale along with previously derived formulas for pyrolysis products.