Theoretical yield and extent of reaction (degree of completion) are important concepts in stoichiometry and in chemical kinetics. We provide expressions describing theoretical yield (Y) and maximum extent of reaction (fractional yield, f[subscript max]) for five examples of commonly encountered reversible chemical reactions: A [equilibrium sign] B; A + B [equilibrium sign] C + D; A + B + C [equilibrium sign] D + E + F; A [equilibrium sign] B + C; and A + B [equilibrium sign] C. We discuss how the equilibrium constant and initial reactant concentration influence the maximum fractional yield (degree of reaction completion) and Y and illustrate their effects on specific examples of reversible reactions: conformer equilibria, esterification reaction, and ionization of weak acids.