| Yobibits per second (Yibit/s) | Zebibits per second (Zibit/s) |
|---|---|
| 1 Yobibit per second | 1024 Zibit/s |
| 2 Yobibits per second | 2048 Zibit/s |
| 3 Yobibits per second | 3072 Zibit/s |
| 4 Yobibits per second | 4096 Zibit/s |
| 5 Yobibits per second | 5120 Zibit/s |
| 10 Yobibits per second | 10240 Zibit/s |
| 20 Yobibits per second | 20480 Zibit/s |
| 25 Yobibits per second | 25600 Zibit/s |
| 50 Yobibits per second | 51200 Zibit/s |
| 100 Yobibits per second | 102400 Zibit/s |
| Reference | Yobibits per second (Yibit/s) | Zebibits per second (Zibit/s) |
|---|---|---|
| A dial-up modem | 4.63221 × 10-20 Yibit/s | 4.74338 × 10-17 Zibit/s |
| Typical home broadband | 8.27181 × 10-17 Yibit/s | 8.47033 × 10-14 Zibit/s |
| Gigabit Ethernet | 8.27181 × 10-16 Yibit/s | 8.47033 × 10-13 Zibit/s |
| Streaming a 4K film | 2.06795 × 10-17 Yibit/s | 2.11758 × 10-14 Zibit/s |
The yobibit per second is a unit of data transfer rate equal to two to the eightieth power bits per second, which is 1,024 zebibits per second. Its symbol is Yibit/s. It is the largest binary transfer rate the International Electrotechnical Commission has named, and the binary counterpart of the yottabit per second.
At this final step the binary and decimal conventions differ by 20.9 per cent, and that number is the conclusion of the argument the IEC prefixes were created to settle. A naming habit that was 2.4 per cent wrong at the kibibit has grown, through eight successive multiplications by 1.024, into a discrepancy of more than a fifth. No measurement system can carry an ambiguity that large.
The unit describes nothing. Global internet traffic runs at roughly an exabit per second, so a yobibit per second is over a million times the total communication of the human species. No link, no aggregate and no forecast reaches it, and none is expected to.
The binary series stops here because the decimal series stopped at yotta when the IEC standard was written in 1998. When ronna and quetta were added to the metric system in 2022, no matching binary names were defined, so a rate of two to the ninetieth bits per second has no accepted short form. That gap will presumably be filled if it is ever needed, which at present it is not.
Defining a rung of a ladder nobody has climbed still has a purpose. A system whose names run out forces its users to improvise, and improvised extensions conflict; writing the whole series out in advance means the rule, rather than a table of exceptions, is all anyone has to learn. That is the same reasoning that gave the metric system its complete prefix set.
For any reader of technical material the lesson of the whole binary series is a single character. Kibit/s, Mibit/s, Gibit/s, Tibit/s, Pibit/s, Eibit/s, Zibit/s and Yibit/s are binary; kbit/s, Mbit/s, Gbit/s, Tbit/s, Pbit/s, Ebit/s, Zbit/s and Ybit/s are decimal; and the difference between them widens from a rounding error to a fifth as you climb.
One yobibit per second equals 1,024 zebibits per second, 151,115,727,451,828,646,838,272 octets per second, or about 1.209 yottabits per second.
The zebibit per second is a unit of data transfer rate equal to two to the seventieth power bits per second, which is 1,024 exbibits per second. Its symbol is Zibit/s. It is the binary counterpart of the zettabit per second, and the two differ by 18.1 per cent — approaching a fifth.
Nothing runs at this rate, and nothing is designed to. A zebibit per second is about a thousand times the total instantaneous traffic of the internet, and it would move the world's entire stock of stored data in a matter of minutes. The unit exists because the IEC series, like the metric series it parallels, was defined completely rather than only as far as anyone then needed.
That completeness is a deliberate design principle rather than an oversight. A measurement system whose names run out at some arbitrary point forces every future user to improvise an extension, and improvised extensions conflict with one another. Defining the whole ladder in advance costs nothing and removes the possibility.
The eighteen per cent gap at this level is the clearest illustration of why the binary series was needed at all. At the kibibit the two conventions differed by 2.4 per cent, which nobody noticed; the discrepancy multiplies by 1.024 at each step, and by here it is large enough that no reader could treat the two labels as interchangeable even in casual writing.
In octets a zebibit per second is 147,573,952,589,676,412,928, or 128 exbioctets per second. Expressing the same rate in every unit on the scale is an exercise rather than an application, but it is one a converter has to perform correctly, because the arithmetic does not become approximate when the quantity becomes unreachable.
The practical lesson is the one the whole binary series teaches: the lowercase i is not optional. It is the only mark in a written figure that distinguishes a power of two from a power of ten, and by this point in the scale the two are nearly a fifth apart.
One zebibit per second equals 1,024 exbibits per second, 147,573,952,589,676,412,928 octets per second, or about 1.181 zettabits per second.