The invention relates to a method and to a device for calibrating a pump (1) provided in a pump line (6), the device comprising an actuator (2) for setting the pumping capacity of the pump (1), and a control unit (3). The device comprises a flow monitor (4) in the fuel line (6). The control unit (3) is designed to substantially steadily vary the controlled variable of the actuator (2), when starting the pump (1), up to the switch point (SP) of the flow monitor (4), and to ascertain and store a controlled variable associated with the respective switch point (SP), to ascertain a controlled variable difference value (Δf) between a reference controlled variable (fR) stored for the pump (1) and the flow monitor (4) and a calibration controlled variable (fK) ascertained during the calibration, and to calibrate the controlled variable of the actuator (2) of the pump (1) based on the controlled variable difference value (Δf).