Capacitances are measured for a level measurement capacitive sensor (18) spanning from a lower end to a higher end of a fluid level measurement range (30), a first capacitive calibration sensor (20) below the fluid level measurement range (30), and a second capacitive calibration sensor (22) above the fluid level measurement range (30). A degree to which the lower end of the fluid level measurement range (30) is immersed in a first fluid and the upper end of the fluid level measurement range (30) is immersed in a second fluid is determined based on a capacitance of the level measurement capacitive sensor (18), a first calibration value characterizing the first fluid and derived from a capacitance of the first capacitive calibration sensor (20), and a second calibration value characterizing the second fluid and derived from a capacitance of the second capacitive calibration sensor (22).