Bit

ComputingCurrent unit

The smallest unit of digital information: a single 0 or 1. Eight bits make a byte.

1 bit = 0.125 bytes (exactly).

1 bit = 0.125 bytes

About the bit

Bit is short for binary digit, and the word was coined by John W. Tukey. He shortened the phrase in a Bell Labs memo dated 9 January 1947. Claude Shannon first used it in print in his 1948 paper A Mathematical Theory of Communication and credited Tukey with the word. The idea predates the name: Ralph Hartley proposed a logarithmic measure of information in 1928, and punched cards, invented by Basile Bouchon and Jean-Baptiste Falcon in 1732 and developed by Joseph Marie Jacquard in 1804, already stored one bit per hole position.

A bit holds one of two values, written 0 or 1, and everything digital is built from them. Eight bits make a byte, so a bit is one eighth of a byte. Symbols for the unit are not settled: the IEC standard uses bit, while IEEE 1541-2002 recommends a lowercase b, with uppercase B reserved for the byte. The difference matters because internet speeds and file sizes are quoted in different units.

Sources: Wikipedia: Bit; NIST: Prefixes for binary multiples

Bit conversion chart

1 bit expressed in every other digital storage unit:

Unit1 bit
Bytes0.125
Kilobytes0.000125
Megabytes1.25×10⁻⁷
Gigabytes1.25×10⁻¹⁰
Terabytes1.25×10⁻¹³
Petabytes1.25×10⁻¹⁶
Kibibytes0.0001220703125
Mebibytes1.192092896×10⁻⁷
Gibibytes1.164153218×10⁻¹⁰
Tebibytes1.136868377×10⁻¹³
Kilobits0.001
Megabits0.000001
Gigabits1×10⁻⁹
Exabytes1.25×10⁻¹⁹
Zettabytes1.25×10⁻²²
Yottabytes1.25×10⁻²⁵
Pebibytes1.110223025×10⁻¹⁶
Exbibytes1.084202172×10⁻¹⁹
Terabits1×10⁻¹²
Kibibits0.0009765625
Mebibits9.536743164×10⁻⁷
Gibibits9.313225746×10⁻¹⁰
Nibbles0.25

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