The invention relates to a mobile communication terminal, advantangeously a mobile phone. According to the invention, the communication terminal includes a barometric altimeter. The altimeter can be recalibrated using means for determining the horizontal position of the mobile communication terminal, and means for determining the ground level at the horizontal position. The invention relates further to a method of calibrating a barometric altimeter of a mobile communication terminal, in which the horizontal position of the mobile communication terminal is determined, the ground level is determined using the determined horizontal position, the atmospheric pressure is measured at the location of the mobile communication terminal and the determined ground level is used to calibrate the barometric altimeter. Further, the invention relates to a method of determining the altitude of a mobile communication terminal, by establishing the horizontal position of the mobile communication terminal and determining the ground level at the horizontal position.