SD card

Secure Digital (SD)

From top to bottom: SD, miniSD, microSD
Media type	Memory card
Capacity	SD: Up to 2 GB SDHC: Up to 32 GB SDXC: Up to 2 TB SDUC: Up to 128 TB
Block size	Variable
Read mechanism	Default: 12.5 MB/s High-speed: 25 MB/s UHS-I: 52 MB/s (SDR50, DDR50) or 104 MB/s (SDR104) UHS-II: 156 MB/s full-duplex or 312 MB/s half-duplex UHS-III: 312 MB/s full-duplex or 624 MB/s half-duplex Express: Up to 3,940 MB/s
Standard	SD Standard
Developed by	SD Association
Dimensions	Standard: 32.0×24.0×2.1 mm (1.260×0.945×0.083 in) 1,612.8 mm3 (0.09842 cu in) Mini: 21.5×20.0×1.4 mm (0.846×0.787×0.055 in) 602 mm3 (0.0367 cu in) Micro: 15.0×11.0×1.0 mm (0.591×0.433×0.039 in) 165 mm3 (0.0101 cu in)
Weight	Standard: ~2 g Mini: ~800 mg Micro: ~250 mg
Usage	Portable devices
Extended from	MultiMediaCard
Released	August 1999

Secure Digital (SD) is a proprietary, non-volatile, flash memory card format developed by the SD Association (SDA). Owing to their compact size, SD cards have been widely adopted in a variety of portable consumer electronics, including digital cameras, camcorders, video game consoles, mobile phones, action cameras, and camera drones.^[1][2]

The SD format was introduced in August 1999 by SanDisk, Panasonic (then Matsushita), and Toshiba. It was designed as a successor to the MultiMediaCard (MMC) format, introducing several improvements aimed at enhancing usability, durability, and performance, which contributed to its rapid emergence as an industry standard.

To manage the licensing and intellectual property rights related to the format, the three companies established SD-3C, LLC. In January 2000, they also founded the SDA, a non-profit organization dedicated to developing and promoting SD card standards.^[3] As of 2023, the SDA includes approximately 1,000 member companies. The SDA uses a suite of SD-3C-owned trademarked logos to enforce compliance with official specifications and to indicate product compatibility.^[4]