The calibration support of your most accurate workload has always been a formidable task. As technical advances make it easier for manufacturers to offer products with state-of-the-art performance, the metrologist must find practical ways to support workload that often pushes the capabilities of the standards available. The test uncertainty ratios (TURs) between the unit under test (UUT) and the standards used can be lower than those recommended by industry standards and practices. Yet, no one can afford to compromise the adequacy and traceability requirements of today’s quality standards. Today’s high-performance digital multimeters, like the popular 8 1 / 2 digit Hewlett-Packard 3458A, are excellent examples of such a challenging workload. This application note describes a process and procedure for fast, practical calibration using the Fluke 5720A Calibrator. Guardbanding, as proposed in draft five of ISO Guide 25, and in other technical literature, offers a technique for addressing low TURs by providing a statistical means to assure, with sufficient confidence, that a calibration is adequate and complies with the manufacturer’s requirements as well as good metrology guidelines. The fact that both the 3458A and the 5720A are conservatively specified, with small deviations from specification center points, and offer quiet and repeatable performance, makes the approach outlined here possible.