bit (b)
1 bit = 0.125 bytes
What is bit?
A bit is the smallest unit of digital information, representing a value of either 0 or 1. It is used to express network bandwidth, signal data rates, and low-level binary data in computing and telecommunications.
Notes: Binary digit
Real-world uses
Bits are the fundamental unit of data transmission. Network speeds (Wi-Fi, fibre broadband, mobile data) are measured in bits per second (bps and its multiples). Colour depth in digital displays is expressed in bits per channel (8-bit colour = 256 shades per channel). Audio resolution is described in bits (16-bit CD, 24-bit studio audio).
History
The term "bit" (contraction of "binary digit") was coined by mathematician John Tukey in 1947. Claude Shannon formalised the concept in his landmark 1948 paper "A Mathematical Theory of Communication," establishing information theory and defining the bit as the fundamental unit of information.
Common mistakes
Confusing bits with bytes — 8 bits = 1 byte. A "100 Mbps" internet connection transfers 100 megabits, or 12.5 megabytes, per second. Capitalisation matters: "b" = bit, "B" = byte, so "Mb" is not the same as "MB".
When is this conversion used?
Converting bit to byte is useful in the data domain when comparing values across different measurement standards or applying formulas that require a specific unit.
How to convert bit to byte
To convert bit to byte, multiply the value by 0.125.
Conversion formula (from base unit)
x * 0.125
Measurement standards
The International Electrotechnical Commission (IEC 80000-13) defines binary prefixes: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes. The SI decimal prefixes (kB = 1,000 bytes, MB = 1,000,000 bytes) apply to data units as they do to all SI quantities.
Did you know?
By 2025, the global datasphere is estimated to reach 181 zettabytes — roughly 181 trillion gigabytes. If stored on standard Blu-ray discs, the stack would reach from Earth to Mars and back over 20 times.
| bits | bytes |
|---|---|
| 0.1 | 0.0125 |
| 0.5 | 0.0625 |
| 1 | 0.125 |
| 2 | 0.25 |
| 5 | 0.625 |
| 10 | 1.25 |
| 25 | 3.125 |
| 50 | 6.25 |
| 100 | 12.5 |
| 250 | 31.25 |
| 500 | 62.5 |
| 1,000 | 125 |
Common values
| bits | bytes | |
|---|---|---|
| A text email | 40,000 bits | 5,000 bytes |
| An MP3 song (4 min) | 32,000,000 bits | 4,000,000 bytes |
| A smartphone photo | 40,000,000 bits | 5,000,000 bytes |
| An HD movie | 4.000000e+10 bits | 5.000000e+09 bytes |
| A full hard drive | 8.000000e+12 bits | 1.000000e+12 bytes |
Full bit conversion table
| Unit | Value | Factor |
|---|---|---|
| byte | 1 b = 0.125 B | × 0.125 |
| kilobyte (decimal) | 1 b = 0.000125 kB | × 0.000125 |
| megabyte (decimal) | 1 b = 1.250000e-07 MB | × 1.250000e-07 |
| gigabyte (decimal) | 1 b = 1.250000e-10 GB | × 1.250000e-10 |
| terabyte (decimal) | 1 b = 1.250000e-13 TB | × 1.250000e-13 |
| kibibyte (binary) | 1 b = 0.00012207 KiB | × 0.00012207 |
| mebibyte (binary) | 1 b = 1.192093e-07 MiB | × 1.192093e-07 |
| gibibyte (binary) | 1 b = 1.164153e-10 GiB | × 1.164153e-10 |
| tebibyte (binary) | 1 b = 1.136868e-13 TiB | × 1.136868e-13 |