What do the symbols on my SD card mean?Updated 9 months ago

Capacities 

The capacity number tells you how much storage space a particular card has. Card capacity is usually given in Gigabytes (GB). 

Read Speed 

Read speed indicates how fast you can read data off the card. A faster read speed equals shorter data transfer times. Read speed is usually given in Megabytes per second (MB/s). 

Write Speed 

Write speed tells you how fast data can be written on the card. Write speeds are also usually given in Megabytes per second (MB/s). 

Bus Interface 

Bus interface refers to the maximum bus speed at which a memory card can transfer data. Almost all SD cards manufactured today have either UHS-I or UHS-II interfaces, marked on the card with the Roman numerals I and II. UHS stands for Ultra High Speed. UHS-I offers data transfer speeds of up to 104MB/s, while UHS-II offers speeds of up to 312MB/s. You can use UHS-II cards in UHS-I-compatible devices, but they won’t be as fast in them.  

Speed Class Ratings 

A speed class rating defines the minimum sequential write speed of the memory card, which is especially important for shooting videos. A memory card must maintain a certain continuous write speed to avoid frame drops and errors during recording.   

The SD Card Association has three Speed Class standards, which you can read more about in the full article here.