A method for determining a fuel mass of a single injection that has been injected into at least one combustion chamber of a combustion engine with at least one injection under high pressure. The method includes determining a correction variable for the single injection with the aid of a comparison of a measure for the actual amount of the injected fuel of at least one test injection, which takes place due to a measure for a default nominal amount of a desired single injection, and a measure for the nominal amount of the test injection. The method additionally includes executing a plurality of timely directly successive test injections.