AbstractWhen a mixture of triacylglycerols and free fatty acids or fatty acid alkyl esters is treated with a random or sn‐1,3 regioselective lipase enzyme, part of these acids will be incorporated into the triacylglycerols while liberating fatty acids that were originally part of these triacylglycerols. Authors generally report the extent of incorporation and then comment on whether equilibrium had been reached and/or acyl migration has been observed. In doing so, they do not refer to articles that provide equations to be used to conclude whether equilibrium has been reached. It is the purpose of the present article to provide these equations and, by using them on literature data, show to what extent conclusions drawn by authors are correct. Besides, the availability of these equations will make it easier to interpret ongoing research on interesterification and to steer its direction in a more appropriate manner.