Units of Computer - Memory

Memory unit is:
* the amount of data that can be stored in the storage unit.
* that in which storage capacity is expressed in terms of Bytes.

Following are the main memory storage units:

Sr.No. Unit Description
1 Bit (Binary Digit)
A binary digit is logical 0 and 1 representing a passive or an active state of a component in an electric circuit.
2 Nibble A group of 4 bits is called nibble.
3 Byte A group of 8 bits is called byte. A byte is the smallest unit which can represent a data item or a character.
4 Word A computer word, like a byte, is a group of fixed number of bits processed as a unit which varies from computer to computer but is fixed for each computer.

The length of a computer word is called word-size or word length and it may be as small as 8 bits or may be as long as 96 bits.


A computer stores the information in the form of computer words.

Few higher storage units are following:

Sr.No. Unit Description
1 Kilobyte (KB)
1 KB = 1024 Bytes
2 Megabyte (MB)
1 MB = 1024 KB
3 GigaByte (GB)
1 GB = 1024 MB
4 TeraByte (TB
1 TB = 1024 GB
5 PetaByte (PB)
1 PB = 1024 TB