A method for determining a rotation angle of a magnet includes measuring a 3D magnetic field vector of a magnetic field generated by the magnet, wherein the 3D magnetic field vector describes at least a part of an ellipse in 3D space during a rotational movement of the magnet. The method further includes mapping the measured 3D magnetic field vector to a 2D vector based on a compensation mapping, wherein the compensation mapping is configured to map the ellipse in 3D space to a circle in 2D space. The method further includes determining the rotation angle of the magnet based on the 2D vector.