The nominal capacity of a memory card is the amount of data that can be written to it. For technical reasons, the real working volume of modern memory cards is usually somewhat less than the nominal one (for example, 14.9 GB with the claimed 16 GB). However, with the same type of card, differences in nominal capacity usually correspond to differences in actual capacity: for example, a 64 GB SDXC card will actually have twice the capacity of a 32 GB card of the same card.
Recall that different types of media have different limits on the maximum volume; see "Type" for details. And a specific volume is most often chosen by the manufacturer not arbitrarily, but from a list of standard options. The most widely used cards nowadays are
16 GB,
32 GB,
64 GB,
128 GB and
256 GB ; capacities of
8 GB or less are considered modest, with the most capacious models holding
512 GB or more.
Note that the price of the card directly depends on this parameter. Thus, many models are available in several variations, differing solely in capacity; and it is worth choosing by volume depending on the types of data that are planned to be stored on the card. Of the popular formats, text documents occupy the least space — usually tens, at most hundreds of kilo
...bytes. The size of a photo from a modern camera or an MP3 file is already calculated in megabytes, music in lossless formats "weighs" already tens of megabytes, and the volume of a video depends on its duration, resolution and the codecs used.
