A bit (binary digit) is the smallest unit of digital information. A bit can have only two values (0 or 1). Originally the name "bigit" was used. The term was probably introduced by a scientist John Tukey in 1949.

Prefixes are used to make the notation of bigger pieces of information easier. Because bits are made up using the binary (base two) number system, their multiples must also be powers of two.

kilo  210  1.024
Mega 220 1.048.576
Giga 230 1.073.741.824
Tera 240 1.099.511.627.776

See also