A method for preparing a hydrocarbylhydrocarbyloxysilane of formula RaHpSi(OR)(4-a-b), where each R is independently a hydrocarbyl group and subscript a is 1 to 4 and subscript b is 1 to 2 is disclosed. The method includes heating ingredients including a hydrocarbyl carbonate and a source of silicon and catalyst. The method can be used to make dimethyldimethoxysilane.