A method and a device, a computer program and a computer program product for implementing a method for calibrating a fuel injector of an internal combustion engine, including the following: a) Specifying a first relationship between an injection quantity and an actuating variable of the fuel injector for implementing the injection quantity, b) Specifying a setpoint injection quantity, c) Specifying at least one setpoint value for the actuating variable of the fuel injector according to the first relationship, or implementing the setpoint injection quantity, d) Determining an indicated work resulting from the implementation of the at least one setpoint value for the actuating variable, e) Comparing a variable as a function of the determined resulting indicated work to an expected value, f) Correcting the at least one setpoint value for the actuating variable of the fuel injector as a function of the comparison result.