The errors of self-calibrating measuring systems are characterized by an optimal value which cannot be further reduced. It depends on the quotient formed by the maximal temporal error rise and the limiting frequency. The temporal error rise results from the aging of the system, the influencing coefficients with regard to perturbations and the corresponding maximal perturbation quantity rises.The error limits can only be reduced efficiently if low error rises are assured by the design, technology balancing, and automatic correction.