ISO 11952:2019 specifies methods for characterizing and calibrating the scan axes of scanning-probe microscopes (SPMs) for measuring geometric quantities at the highest level. It is applicable to those providing further calibrations and is not intended for general industry use, where a lower level of calibration might be required.This document has the following objectives:— to increase the comparability of measurements of geometrical quantities made using SPMs by traceability to the unit of length;— to define the minimum requirements for the calibration process and the conditions of acceptance;— to ascertain the instrument's ability to be calibrated (assignment of a "calibrate-ability" category to the instrument);— to define the scope of the calibration (conditions of measurement and environments, ranges of measurement, temporal stability, transferability);— to provide a model, in accordance with ISO/IEC Guide 98-3, to calculate the uncertainty for simple geometrical quantities in measurements using an SPM;— to define the requirements for reporting results.