A large number of modern devices contains permanent magnets, such as various types of magnetic sensors or motors. For the design and optimization purposes of all these devices one needs to know a very precise distribution of the magnetic field of the used magnets. These fields are often extremely inhomogeneous. For this reason it is necessary to build a magnetic field sensor that measures the magnetic flux density vector practically in a single spot. The solution to this problem is found in application of the integrated 3-axis Hall-sensor. Another problem that is described in this paper relates to the calibration of the integrated 3-axis Hall-effect sensors. For the calibration purpose there are designed the Calibration tools that reference the position of the Magnetic Field Sensitive Volume of the applied 3D Hall sensor respectively to the reference coordinate system of the Mappers, as well as the Calibration tools for the calibration and reduction of the angular errors. The Hall voltages from integrated 3-axis Hall sensor are being successively measured by placing the sensor in the Calibration Cube and rotating it. Based on these measurements it is possible to determine all 9 components of the Sensitivity matrix. A later on, during the mapping process, the measurement results can be calculated using the inverse sensitivity matrix, so that the final result corresponds to the real reference coordinate system.