| Zebibits per second (Zibit/s) | Yottabits per second (Ybit/s) |
|---|---|
| 1 Zebibit per second | 0.00118059162072 Ybit/s |
| 2 Zebibits per second | 0.00236118324143 Ybit/s |
| 3 Zebibits per second | 0.00354177486215 Ybit/s |
| 4 Zebibits per second | 0.00472236648287 Ybit/s |
| 5 Zebibits per second | 0.00590295810359 Ybit/s |
| 10 Zebibits per second | 0.0118059162072 Ybit/s |
| 20 Zebibits per second | 0.0236118324143 Ybit/s |
| 25 Zebibits per second | 0.0295147905179 Ybit/s |
| 50 Zebibits per second | 0.0590295810359 Ybit/s |
| 100 Zebibits per second | 0.118059162072 Ybit/s |
| Reference | Zebibits per second (Zibit/s) | Yottabits per second (Ybit/s) |
|---|---|---|
| A dial-up modem | 4.74338 × 10-17 Zibit/s | 5.6 × 10-20 Ybit/s |
| Typical home broadband | 8.47033 × 10-14 Zibit/s | 1 × 10-16 Ybit/s |
| Gigabit Ethernet | 8.47033 × 10-13 Zibit/s | 1 × 10-15 Ybit/s |
| Streaming a 4K film | 2.11758 × 10-14 Zibit/s | 2.5 × 10-17 Ybit/s |
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.
The yottabit per second is a unit of data transfer rate equal to a thousand zettabits per second. Its symbol is Ybit/s. For thirty years it was the largest rate the metric system could name, and it describes a speed that has no application anywhere: not in engineering, not in research, and not in any forecast that anyone takes seriously.
Its distance from reality is easy to state. Global internet traffic averages roughly one exabit per second, so a yottabit per second is about a million times the combined communication of the entire human species. The largest single link ever built runs at a few hundred terabits per second, which is a ten-billionth of this figure.
The unit is nonetheless properly defined, and that completeness is the point. The metric system's rule is that every prefix combines with every unit without exception, so a reader who has never seen Ybit/s can decode it from the prefix alone. A system with gaps would need a table of which combinations are legal, and a table is exactly what a rule-based system exists to avoid.
There is a physical way to think about the number. A yottabit per second is 125 zettaoctets per second, and the total quantity of data humanity has ever stored is a few hundred zettaoctets. A link at this rate would therefore transmit the entire accumulated information of the species in a couple of seconds. No such body of data exists in one place to be sent, and nothing at the far end could receive it.
The prefix yotta was adopted in 1991 alongside zetta, at a conference that also had to consider which letters remained free. It stood at the top of the metric ladder until 2022, when ronna and quetta were added above it, partly because data quantities were beginning to approach the old ceiling. Rates have not followed quantities upward at the same pace.
For a converter, handling the unit is a matter of consistency rather than utility. A tool that converts every metric prefix correctly does not need to decide which of them anyone will use, and a figure written in yottabits per second — however unlikely — converts by the same rule as any other.
One yottabit per second equals 1,000 zettabits per second, 125 zettaoctets per second, or about 0.8272 yobibits per second.