| Yobibits (Yibit) | Yottaoctets (Yo) |
|---|---|
| 1 Yobibit | 0.151115727452 Yo |
| 2 Yobibits | 0.302231454904 Yo |
| 3 Yobibits | 0.453347182355 Yo |
| 4 Yobibits | 0.604462909807 Yo |
| 5 Yobibits | 0.755578637259 Yo |
| 10 Yobibits | 1.51115727452 Yo |
| 20 Yobibits | 3.02231454904 Yo |
| 25 Yobibits | 3.7778931863 Yo |
| 50 Yobibits | 7.55578637259 Yo |
| 100 Yobibits | 15.1115727452 Yo |
| Reference | Yobibits (Yibit) | Yottaoctets (Yo) |
|---|---|---|
| A plain text message (160 characters) | 1.05879 × 10-21 Yibit | 1.6 × 10-22 Yo |
| A three-minute MP3 | 1.98523 × 10-17 Yibit | 3 × 10-18 Yo |
| A smartphone photo | 2.64698 × 10-17 Yibit | 4 × 10-18 Yo |
| A high-definition film | 2.64698 × 10-14 Yibit | 4 × 10-15 Yo |
| A dual-layer Blu-ray disc | 3.30872 × 10-13 Yibit | 5 × 10-14 Yo |
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 yottaoctet is a unit of digital information equal to a thousand zettaoctets, or a septillion octets — a one followed by twenty-four zeros. Its symbol is Yo. Nothing that exists is measured in yottaoctets; the unit describes a quantity of data the world has not yet produced.
The total data held by humanity is currently estimated in the low hundreds of zettaoctets, so the world is a small fraction of the way to its first yottaoctet. On the growth rates of the last two decades, that threshold would be crossed sometime in the 2040s, though every long-range forecast in this field has been wrong in both directions.
The physical obstacles are severe. At the storage densities of current hard drives, a yottaoctet would need something like a hundred billion units. Manufacturing them at present rates would take centuries, powering them would need the electrical output of many countries, and housing them would require a building programme without precedent. The number is not absurd, but it is far beyond the current industrial base.
Research into higher-density storage exists partly because of this ceiling. DNA data storage, which encodes information in synthetic genetic sequences, offers densities millions of times higher than magnetic media, and a yottaoctet of DNA would fit in a room rather than a continent. Reading and writing it remain slow and costly, but the density argument is what keeps the field funded.
The yottaoctet also appears in claims that turn out to be exaggerated. Reports that intelligence agencies were building yottaoctet-scale facilities circulated widely in the 2010s and were not supported by the construction, the power supply or the storage market. Any claim about a yottaoctet of anything can be checked against total world manufacturing, which is a useful discipline.
Between 1991 and 2022 the yotta prefix was the top of the metric ladder, which is why it was the natural unit for speculative claims. The addition of ronna and quetta in 2022 gave the system three more decimal orders above it, and it is telling that this was done partly because data quantities were approaching the old ceiling.
One yottaoctet equals 1,000 zettaoctets, 1,000,000,000,000,000 gigaoctets, 8 yottabits, or about 0.8272 yobioctets.