IEC 62830-8:2021(E) specifies terms, definitions, symbols, test, and evaluation methods used to determine the performance characteristics of flexible and stretchable supercapacitor for practical use in low power electronics such as energy storage devices for energy harvesting, flexible and stretchable electronics, low-power devices, IoT applications, etc. This document is applicable to all the flexible and stretchable supercapacitor for consumers and manufacturers, without any limitations of device technology and size.