This method of converting a computational formula having been acquired in the form of a tree structure containing at least one node associated with a parameterized conditional branching operation and connected to at least a first and a second child node, the child node which is associated with the operation which is not executed and the set of nodes which have this child node as parent node being called ‘dead branch’, this method comprising: —the identification and the deletion (198) of the dead branch corresponding to the acquired value of a conditional parameter so as to obtain a computational formula pruned of this dead branch, and—the compilation (208) of the computational formula pruned of the dead branch so as to obtain the code executable by a chip card.