| Kibibits (Kibit) | Gibibits (Gibit) |
|---|---|
| 1 Kibibit | 0.000000953674316406 Gibit |
| 2 Kibibits | 0.00000190734863281 Gibit |
| 3 Kibibits | 0.00000286102294922 Gibit |
| 4 Kibibits | 0.00000381469726562 Gibit |
| 5 Kibibits | 0.00000476837158203 Gibit |
| 10 Kibibits | 0.00000953674316406 Gibit |
| 20 Kibibits | 0.0000190734863281 Gibit |
| 25 Kibibits | 0.0000238418579102 Gibit |
| 50 Kibibits | 0.0000476837158203 Gibit |
| 100 Kibibits | 0.0000953674316406 Gibit |
| Reference | Kibibits (Kibit) | Gibibits (Gibit) |
|---|---|---|
| A plain text message (160 characters) | 1.25 Kibit | 0.00000119209 Gibit |
| A three-minute MP3 | 23437.5 Kibit | 0.0223517 Gibit |
| A smartphone photo | 31250 Kibit | 0.0298023 Gibit |
| A high-definition film | 31250000 Kibit | 29.8023 Gibit |
| A dual-layer Blu-ray disc | 390625000 Kibit | 372.529 Gibit |
The kibibit is a unit of digital information equal to 1,024 bits. Its symbol is Kibit. It is the first of the binary prefixes, a set of units defined by the International Electrotechnical Commission in 1998 to end a confusion that had run through computing since the 1960s.
The problem was straightforward. Computers address memory in powers of two, so memory came in chunks of 1,024 rather than 1,000. Engineers borrowed the metric prefix kilo for that quantity because 1,024 is close to 1,000, and for small numbers the approximation was harmless. But storage and transmission counted in true thousands, so the same prefix meant two different things depending on which part of the machine was being described.
The IEC's solution was to coin new names. Kibi is a contraction of kilo binary, and the pattern continues with mebi, gibi, tebi, pebi, exbi, zebi and yobi. Each is 1,024 times the one below, and each symbol takes the form of a capital letter followed by a lowercase i: Ki, Mi, Gi, Ti and so on. The kilobit then means one thousand bits and nothing else.
A kibibit is 128 octets, and the gap from a kilobit is 2.4 per cent. That small difference is why the two were confused for so long: at this scale nobody notices. The error compounds by 2.4 per cent at every step, reaching 5 per cent at the mebibit, 7 per cent at the gibibit and 21 per cent by the yobibit, which is where the ambiguity became genuinely expensive.
Adoption has been partial and uneven. Standards bodies, the Linux kernel and most technical documentation use the IEC prefixes correctly. Consumer software largely does not, and many programs still write KB while dividing by 1,024. The result is that a reader must often infer from context which convention a number follows, which is exactly what the standard was written to prevent.
In practice the kibibit itself appears mainly in the specifications of small memory chips, in serial memory used by embedded systems, and in protocol documents where an exact power of two matters. Anywhere the number 1,024 is meant rather than 1,000, this is the correct unit.
One kibibit equals 1,024 bits, 128 octets, or 1.024 kilobits.
The gibibit is a unit of digital information equal to 1,073,741,824 bits, which is 1,024 mebibits or two to the thirtieth power. Its symbol is Gibit. It is the binary counterpart of the gigabit, and the two now differ by 7.4 per cent — a gap wide enough that mistaking one for the other in a purchase order is a genuine error.
Its practical home is the memory industry. Dynamic memory chips are made in binary capacities because their internal organisation is a rectangular grid of rows and columns, both addressed in binary. A part described as 8 gigabits in marketing material is an 8-gibibit die, holding 8,589,934,592 bits, and eight of those make the 8 gibioctets a memory module advertises as 8 GB.
Flash memory follows the same rule for the same reason, though with a twist: flash dies include spare blocks to replace cells that wear out, so the usable capacity of a drive is deliberately less than the raw capacity of its chips. Manufacturers then quote the usable figure in decimal units, which is how a drive built from binary parts ends up labelled with a decimal number.
The 7.4 per cent gap explains a great deal of everyday confusion. A memory module of 8 gibioctets and a solid-state drive of 8 gigaoctets are not the same size, though both are written 8 GB. The module holds 8.59 gigaoctets; the drive holds 8.00. Nothing is wrong with either figure, but they are counted in different bases and cannot be compared without conversion.
A gibibit is 134,217,728 octets, or 128 mebioctets. In everyday terms that is roughly a hundred and thirty megaoctets — a couple of dozen photographs, or two minutes of high-definition video. It is not a large amount of data by modern standards, which is why the unit appears in component specifications rather than in descriptions of files.
The correct symbol, Gibit, is used in datasheets and in standards but almost never in advertising. When a document writes Gb without further explanation, the safe assumption is that memory means the binary quantity and networking means the decimal one, and that a careful writer would have written Gibit or Gbit to say which.
One gibibit equals 1,073,741,824 bits, 1,024 mebibits, 134,217,728 octets, or about 1.074 gigabits.