A pressure sensor includes a micromechanical sensor element including a pressure-sensitive diaphragm, which spans a cavity in a base material and includes a diaphragm electrode. A fixed counter electrode is situated inside the cavity and, with the diaphragm electrode, forms a first measuring capacitor for detecting a first measuring pressure. A reference capacitor is situated inside the cavity and includes a first and a second fixed reference electrode. The pressure sensor is operable in a first operating mode, in which the first measuring capacitor and the first reference capacitor are interconnected in a first bridge circuit. The pressure sensor is operable in a second operating mode, in which the diaphragm electrode, the counter electrode and the reference electrodes are interconnected in such a way that the diaphragm electrode, together with the at least one first reference electrode, forms a second measuring capacitor for detecting a second measuring pressure.