The invention relates to a dialysis machine having an extracorporeal blood circuit in which a dialyzer, a blood pump, and an arterial pressure sensor are arranged, wherein the dialysis machine furthermore has a compensation device by means of which the set value for the blood flow through the extracorporeal circuit can be corrected to a compensated value using the arterial blood pressure； wherein the dialysis machine furthermore has recognition means which are configured to recognize whether the arterial pressure sensor is connected to the extracorporeal blood circuit or not； and wherein the dialysis machine has an estimator unit which is configured to estimate a value for the arterial blood pressure if it is recognized by the recognition means that the arterial pressure sensor is not connected to the extracorporeal blood circuit.
