| Yobibits (Yibit) | Kibibits (Kibit) |
|---|---|
| 1 Yobibit | 1.18059162072 × 1021 Kibit |
| 2 Yobibits | 2.36118324143 × 1021 Kibit |
| 3 Yobibits | 3.54177486215 × 1021 Kibit |
| 4 Yobibits | 4.72236648287 × 1021 Kibit |
| 5 Yobibits | 5.90295810359 × 1021 Kibit |
| 10 Yobibits | 1.18059162072 × 1022 Kibit |
| 20 Yobibits | 2.36118324143 × 1022 Kibit |
| 25 Yobibits | 2.95147905179 × 1022 Kibit |
| 50 Yobibits | 5.90295810359 × 1022 Kibit |
| 100 Yobibits | 1.18059162072 × 1023 Kibit |
| Reference | Yobibits (Yibit) | Kibibits (Kibit) |
|---|---|---|
| A plain text message (160 characters) | 1.05879 × 10-21 Yibit | 1.25 Kibit |
| A three-minute MP3 | 1.98523 × 10-17 Yibit | 23437.5 Kibit |
| A smartphone photo | 2.64698 × 10-17 Yibit | 31250 Kibit |
| A high-definition film | 2.64698 × 10-14 Yibit | 31250000 Kibit |
| A dual-layer Blu-ray disc | 3.30872 × 10-13 Yibit | 390625000 Kibit |
The yobibit is a unit of digital information equal to two to the eightieth power bits, which is 1,024 zebibits. Its symbol is Yibit. It is the largest of the binary prefixes defined by the International Electrotechnical Commission, and the binary counterpart of the yottabit.
At this step the two conventions differ by 20.9 per cent. That gap is the culmination of the argument for the binary prefixes: a naming habit that was 2.4 per cent wrong at the kibibit is now a fifth wrong, which no engineering document can tolerate. The IEC series stops here because the decimal series stopped at yotta when it was defined in 1998.
When the metric system gained ronna and quetta in 2022, the binary series was not extended to match. There are no accepted names above yobi, so a quantity of two to the ninetieth bits has no short form and must be written out. This is a gap in the system that will presumably be filled when someone needs it, though at present nothing comes close.
A yobibit is 151,115,727,451,828,646,838,272 octets, or 128 zebioctets. The world's entire stock of data is somewhere in the low hundreds of zettaoctets, which is a fraction of a per cent of a yobioctet. Nothing at this scale has been built, is being built, or is presently planned.
The unit is nevertheless properly defined, and that completeness has a purpose. A measurement system whose rules run out at a certain size forces every future user to invent an extension, and competing extensions are how ambiguity begins. Defining the whole ladder in advance costs nothing and prevents that.
For anyone reading technical documents, the practical lesson of the whole binary series is the lowercase i. Kibit, Mibit, Gibit, Tibit, Pibit, Eibit, Zibit and Yibit are binary; kbit, Mbit, Gbit, Tbit, Pbit, Ebit, Zbit and Ybit are decimal; and the difference between them grows from negligible to a fifth as you climb. A writer who omits the i has left the reader to guess.
One yobibit equals 1,024 zebibits, 151,115,727,451,828,646,838,272 octets, or about 1.209 yottabits.
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.