| Zettabits per second (Zbit/s) | Tebibits per second (Tibit/s) |
|---|---|
| 1 Zettabit per second | 909494701.773 Tibit/s |
| 2 Zettabits per second | 1818989403.55 Tibit/s |
| 3 Zettabits per second | 2728484105.32 Tibit/s |
| 4 Zettabits per second | 3637978807.09 Tibit/s |
| 5 Zettabits per second | 4547473508.86 Tibit/s |
| 10 Zettabits per second | 9094947017.73 Tibit/s |
| 20 Zettabits per second | 18189894035.5 Tibit/s |
| 25 Zettabits per second | 22737367544.3 Tibit/s |
| 50 Zettabits per second | 45474735088.6 Tibit/s |
| 100 Zettabits per second | 90949470177.3 Tibit/s |
| Reference | Zettabits per second (Zbit/s) | Tebibits per second (Tibit/s) |
|---|---|---|
| A dial-up modem | 5.6 × 10-17 Zbit/s | 0.0000000509317 Tibit/s |
| Typical home broadband | 1 × 10-13 Zbit/s | 0.0000909495 Tibit/s |
| Gigabit Ethernet | 1 × 10-12 Zbit/s | 0.000909495 Tibit/s |
| Streaming a 4K film | 2.5 × 10-14 Zbit/s | 0.0000227374 Tibit/s |
The zettabit per second is a unit of data transfer rate equal to a thousand exabits per second. Its symbol is Zbit/s. No system on Earth moves data at this rate, and none is planned; the unit exists because the metric system defines every prefix for every unit, whether or not the combination has yet been needed.
To see how far off it is, take the whole internet. Global traffic at present runs at roughly one exabit per second on average, so the entire planet's communications would have to grow a thousandfold to reach one zettabit per second. At the growth rates of the last two decades that would take somewhere between twenty and thirty years, which is precisely the sort of extrapolation that has been wrong in both directions before.
A zettabit per second is 125 exaoctets per second. Since global data storage manufacturing runs at a few hundred exaoctets a year, a link at this rate would transfer the world's entire annual production of new storage capacity in a couple of seconds. Nothing could be stored at the far end; the data would have to be processed and discarded as it arrived.
That last point is not as fanciful as it sounds. Several existing systems already discard almost everything they receive: particle detectors, radio telescope arrays and network monitoring systems all process far more than they keep, because keeping it is impossible and unnecessary. A zettabit-per-second link would be an extreme case of an architecture that already exists.
The physical obstacles are less absolute than they might appear. The theoretical capacity of a single optical fibre is far above what is used today, and the practical limits come from amplifier noise, non-linear effects and the electronics at each end rather than from the glass itself. Aggregating enough fibres would reach a zettabit per second; the difficulty is that nobody has a reason to.
For a converter, the unit matters because forecasts and capacity models are written in whatever unit keeps the numbers legible. A projection that reaches into the 2050s may reasonably state totals in zettabits per second, and a reader needs to be able to convert that into something familiar.
One zettabit per second equals 1,000 exabits per second, 125 exaoctets per second, or about 0.8470 zebibits per second.
The tebibit per second is a unit of data transfer rate equal to 1,099,511,627,776 bits per second, which is 1,024 gibibits per second. Its symbol is Tibit/s. It is the binary counterpart of the terabit per second, and the two differ by 10 per cent.
Ten per cent is the point at which the distinction becomes a matter of money rather than of pedantry. A supplier quoting a system at a hundred terabits per second and a customer measuring a hundred tebibits per second are not describing the same performance, and the difference is ten terabits — more than most organisations' entire external connectivity.
The rate belongs to the interior of very large machines. The aggregate memory bandwidth of a rack of accelerators, or the internal switching capacity of a large network chip, reaches this range, and both are built from power-of-two structures: memory channels of fixed binary width, switch ports in powers of two, buffers sized in binary. Expressing their totals with binary prefixes preserves the arithmetic that produced them.
In octets a tebibit per second is 137,438,953,472, or 128 gibioctets per second. That is more than any single storage device can supply and more than any external cable carries. It is a figure that describes something happening inside a cabinet, between chips connected by short traces on a board, where the physical distance is measured in centimetres.
Optical research also brushes this range. A laboratory demonstration carrying a petabit per second down one fibre is a thousand times higher, but individual wavelength channels and the electronics driving them work at tebibit-scale aggregates, and papers reporting them often state the binary figure because the underlying frame sizes are binary.
The habit of writing the lowercase i is worth keeping even where the reader is unlikely to check. A number written unambiguously can be converted correctly by anyone who reads it later; one written ambiguously cannot be repaired, and at ten per cent the ambiguity is no longer harmless.
One tebibit per second equals 1,024 gibibits per second, 137,438,953,472 octets per second, or about 1.100 terabits per second.