What Is an SD Card Adapter?

By Thomas Ferraioli

An SD card adapter allows a microSD or miniSD card to fit into a traditional-size SD slot on a computer, PDA, camcorder, cell phone or similar electronic device.


Micro SD and mini SD cards were created to meet the ever-increasing demand for smaller storage devices to fit into mobile phones, according to the SD Association, founded by Panasonic, SanDisk Corporation and Toshiba Corporation (see link in Resources). To allow the smaller cards to fit into other devices for data transfer, the adapter is necessary.

Size of the Standard SD Card

A traditional SD card is about the size of a postage stamp at 24mm by 32mm and is 2.1mm thick.

Size of the MiniSD Card

The MiniSD card is about 37 percent smalle, at 21.5mm by 20mm and is 1.4mm thick.

Size of the MicroSD Card

The MicroSD card, the smallest of the three, is 25 percent the size of the original SD card and measures 15mm by 11mm and is 1mm thick.


SDXC cards, according to the SD Association, have a 2009 release and will be available in SD and microSD sizes with a capacity range from 32GB to 2TB (terabytes). As with other SD cards, the adapter will allow the microSDXC card to fit into standard SD card slots.

References & Resources