The basic data storage unit, the bit, can take one of two values (0 or 1). Since a bit can store an extremely small amount of information, more common units of data quantity, the byte and its multiples, are used.
 

	Unit   Nibble   1 Nibble   4 bits         Octet   1 Octet   8 bits         Byte   1 B   8 bits         Kilobyte   1 KB   1024 Bytes         Megabyte   1 MB   1024 Kilobytes   1,048,576 Bytes     Gigabyte   1 GB   1024 Megabytes   1,073,741,824 Bytes     Terabyte   1 TB   1024 Gigabytes   1,099,511,627,776 Bytes     Petabyte   1 PB   1024 Terabytes   1,125,899,906,842,624 Bytes     Exabyte   1 XB   1024 Petabytes   1,152,921,504,606,846,976 Bytes     Zettabyte   1 ZB   1024 Exabytes   1,180,591,620,717,411,303,424 Bytes     Yottabyte   1 YB   1024 Zettabytes   1,208,925,819,614,629,174,706,176 Bytes

Although rarely used, data storage units based on the bit are sometimes useful in describing quantities of stored information. To easily distinguish bits from bytes, in units' abbreviations bits are always marked in small letters (Kb = kilobit; KB = kilobyte).
 

	Unit   Kilobit   1 Kb   1024 bits     Megabit   1 Mb   1,048,576 bits     Gigabit   1 Gb   1,073,741,824 bits