In the first ever commentary on the Groundwork, one of Kant’s earliest critics, Gottlob August Tittel, argues that the categorical imperative is not a new principle of morality, but merely a new formula. This objection has been unjustly neglected in the secondary literature, despite the fact that Kant explicitly responds to it in a footnote in the second Critique. In this paper I seek to offer a thorough explanation of both Tittel’s ‘new formula’ objection and Kant’s response to it, as well as illustrate its significance. I argue that the objection is in fact the third step in a line of argument that Tittel presents in his commentary, and that the objection is best understood within this context. I analyze Kant’s response in the second Critique footnote line-by-line so as to show that Kant both clarifies that it was never his aim to offer a new principle, but only ‘establish’ the principle that common human reason already implicitly employs. Furthermore, I show that Kant uses the opportunity to clarify the sense in which the categorical imperative is a ‘formula [Formel]’, namely as a representation of a complicated and abstract principle, like the moral law, in a way that is easier to understand and apply. I conclude by illustrating the fourth step in Tittel’s line of argument, which makes the overall significance of the ‘new formula’ objection clear: for Tittel, the problem is not that Kant seems to be offering merely a new formula, but that the categorical imperative lacks a foundation.