MicroSD: Definition & explanation

MicroSD cards are tiny flash storage media inserted into a card slot on smartphones, tablets, or cameras. They use NAND flash technology and transfer data through a standardized contact area. Capacities range from a few gigabytes up to 1.5 terabytes, with standards like SDHC, SDXC, and SDUC defining the size class. Speed classes such as UHS-I, UHS-II, or A1/A2 (App Performance) indicate transfer rates, which matter for app load times or 4K video recording. Compared to a phone's internal UFS storage, MicroSD is noticeably slower but cheaper per gigabyte and removable. Many Android manufacturers have dropped the MicroSD slot to save space and favor faster internal storage; iPhones never support MicroSD. Where available, cards can be used as expandable storage or, on older Android versions, even formatted as internal storage (adopted storage). Despite being less common now, MicroSD remains a simple, affordable way to add capacity, back up files, or move data between devices without cloud access.