The computer implemented method, system or computer program product comprises collecting magnetometer data from the device; and calculating a center of a shape of the magnetometer data as a result of minimization. The minimization of calculating the center of the shape further comprises calculating a plurality of running sums of the magnetometer data; storing the plurality of running sums; storing a count of the number of terms in each of the running sums; and calculating the center of the shape and setting the estimated magnetometer bias to the center of the shape. The radius of the sphere is calculated to ensure accuracy in the estimator of the magnetometer bias.