A device and a method for actuating an injector in a fuel-injection system of an internal combustion engine are described. Using a first calibration method and based on a control parameter, an injector parameter which characterizes the injection process is determined. Starting from this injector parameter, a first feature is determined for calibrating the injector. A second calibration method determines a second feature for calibrating the injector, based on an engine parameter. The first calibration method is monitored on the basis of the second feature.