Metrology is the science of measurement. It covers all theoretical and practical aspects of measurements, whatever the fields and applications. In the modern society, every aspect of our life will inevitably involve metrology. For example, our mobile phones are full of sensors to measure acceleration, rotational speed, light, sound and even altitude and magnetic field. Your smart watch can measure your heart rate and blood oxygen level besides telling you the time. You purchase food from the supermarket and numerous tests have been conducted on them by analysts behind the scene. Also, in time of pandemics, metrology has come to our defense. In this symposium, we have selected several interesting topics around our daily life to share how metrology plays its role. Taking this opportunity, the recent development in the transformation of the International System of Units (SI) to the digital world led by the International Committee for Weights and Measures (CIPM) will also be reported in this symposium.