Browse Definitions :
Definition

bit (binary digit)

What is a bit (binary digit)?

A bit (binary digit) is the smallest unit of data that a computer can process and store. A bit is always in one of two physical states, similar to an on/off light switch. The state is represented by a single binary value, usually a 0 or 1. However, the state might also be represented by yes/no, on/off or true/false. Bits are stored in memory through the use of capacitors that hold electrical charges. The charge determines the state of each bit, which, in turn, determines the bit's value.

Although a computer might be able to test and manipulate data at the bit level, most systems process and store data in bytes. A byte is a sequence of eight bits that are treated as a single unit. References to a computer's memory and storage are always in terms of bytes. For example, a storage device might be able to store 1 terabyte (TB) of data, which is equal to 1,000,000 megabytes (MB). To bring this into perspective, 1 MB equals 1 million bytes, or 8 million bits. That means a 1 TB drive can store 8 trillion bits of data.

How a bit works

Each bit in a byte is assigned a specific value, which is referred to as the place value. A byte's place values are used to determine the meaning of the byte as a whole, based on the individual bits. In other words, the byte values indicate what character is associated with that byte.

A place value is assigned to each bit in a right-to-left pattern, starting with 1 and increasing the value by doubling it for each bit, as described in this table.

Bit position (right to left) Place value

Bit 1

1

Bit 2

2

Bit 3

4

Bit 4

8

Bit 5

16

Bit 6

32

Bit 7

64

Bit 8

128

The place values are used in conjunction with the bit values to arrive at the byte's overall meaning. To calculate this value, the place values associated with each 1 bit are added together. This total corresponds to a character in the applicable character set. A single byte can support up to 256 unique characters, starting with the 00000000 byte and ending with the 11111111 byte. The various combinations of bit patterns provide a range of 0 to 255, which means that each byte can support up to 256 unique bit patterns.

For example, the uppercase "S" in the American Standard Code for Information Interchange (ASCII) character set is assigned the decimal value of 83, which is equivalent to the binary value of 01010011. This figure shows the letter "S" byte and the corresponding place values.

the letter
Diagram illustrating the letter

The "S" byte includes four 1 bits and four 0 bits. When added together, the place values associated with 1 bits total 83, which corresponds to the decimal value assigned to the ASCII uppercase "S" character. The place values associated with the 0 bits are not added into the byte total.

Because a single byte supports only 256 unique characters, some character sets use multiple bytes per character. For example, Unicode Transformation Format character sets use between 1 and 4 bytes per character, depending on the specific character and character set. Despite these differences, however, all character sets rely on the convention of 8 bits per byte, with each bit in either a 1 or 0 state.

The term octet is sometimes used instead of byte, and the term nibble is occasionally used when referring to a 4-bit unit, although it's not as common as it once was. In addition, the term word is often used to describe two or more consecutive bytes. A word is usually 16, 32 or 64 bits long.

In telecommunications, the bit rate is the number of bits that is transmitted in a given time period, usually as the number of bits per second or some derivative, such as kilobits per second.

See also: most significant bit or byte, bitwise, bit stuffing, bit rot, bit slicing, qubit, how many bytes for and classical computing.

This was last updated in June 2022

Continue Reading About bit (binary digit)

Networking
  • firewall as a service (FWaaS)

    Firewall as a service (FWaaS), also known as a cloud firewall, is a service that provides cloud-based network traffic analysis ...

  • private 5G

    Private 5G is a wireless network technology that delivers 5G cellular connectivity for private network use cases.

  • NFVi (network functions virtualization infrastructure)

    NFVi (network functions virtualization infrastructure) encompasses all of the networking hardware and software needed to support ...

Security
  • phishing

    Phishing is a fraudulent practice in which an attacker masquerades as a reputable entity or person in an email or other form of ...

  • computer forensics (cyber forensics)

    Computer forensics is the application of investigation and analysis techniques to gather and preserve evidence from a particular ...

  • cybersecurity

    Cybersecurity is the practice of protecting internet-connected systems such as hardware, software and data from cyberthreats.

CIO
HRSoftware
  • OKRs (Objectives and Key Results)

    OKRs (Objectives and Key Results) encourage companies to set, communicate and monitor organizational goals and results in an ...

  • cognitive diversity

    Cognitive diversity is the inclusion of people who have different styles of problem-solving and can offer unique perspectives ...

  • reference checking software

    Reference checking software is programming that automates the process of contacting and questioning the references of job ...

Customer Experience
  • martech (marketing technology)

    Martech (marketing technology) refers to the integration of software tools, platforms, and applications designed to streamline ...

  • transactional marketing

    Transactional marketing is a business strategy that focuses on single, point-of-sale transactions.

  • customer profiling

    Customer profiling is the detailed and systematic process of constructing a clear portrait of a company's ideal customer by ...

Close