How Much Does a 16Gb SanDisk Memory Card Hold?
By John Lister
Sandisk produces a range of memory cards in the Secure Digital, or SD, format. These include micro-SD cards, which have the same storage capacity but are physically smaller. The precise amount of data that can be stored on a particular model card varies slightly because of technical reasons. How this translates to particular types of files depends on the specifics of the file, though SanDisk gives sample details for its 16GB model.
The definition of a gigabyte varies depending on the measurement used. The giga-prefix technically means billion, meaning 1GB would be 1 billion bytes. In computing context, giga is sometimes used in a system of multiples (2, 4, 8, 16 etc), meaning a gigabyte refers to 1,073,741,824 bytes: 7.3 percent more than the other measure. SanDisk uses the former measure, meaning a 16GB disk has a capacity of 16 billion bytes. The formatting details on the disk take up some space, meaning the true capacity available to the user is a little less than this.
SanDisk suggests a 16GB card can hold 4,000 songs of an average of 3.5 minutes each. The actual amount depends on the bitrate, which affects the quality of the song. As an example, default iTunes tracks are recorded at 128 kbps, which would work out at 4,760 songs at 3.5 minutes each. The higher-quality iTunes Plus service uses 256 kbps, which would mean 2,380 songs.
SanDisk suggests 64 hours of video would fit on a 16GB card, based on the video being recorded at 384 kbps. The actual bitrate of video depends on the format used to encode it and the size of the video in pixels. The quoted 384 kbps is a low estimate. YouTube suggests encoding at a minimum bit rate of 1,000 kbps for its lowest-resolution format. For a full high-definition video it recommends a minimum bitrate of 8,000 kbps plus 284 kbps for stereo audio. This would translate to around 4 hours and 17 minutes on a 16GB card.
SanDisk suggests a 16GB card could hold 10,400 photos taken at a 5-megapixel resolution. This is a common resolution on smartphone cameras and mid-range digital cameras. More expensive camera phones have a higher resolution. For example, the Galaxy S3, which supports SD cards, has an 8-megapixel camera, which would reduce the capacity to 6,500 photos.
A professional writer since 1998 with a Bachelor of Arts in journalism, John Lister ran the press department for the Plain English Campaign until 2005. He then worked as a freelance writer with credits including national newspapers, magazines and online work. He specializes in technology and communications.