| Zettabits per second (Zbit/s) | Gibibits per second (Gibit/s) |
|---|---|
| 1 Zettabit per second | 931322574615 Gibit/s |
| 2 Zettabits per second | 1862645149231 Gibit/s |
| 3 Zettabits per second | 2793967723846 Gibit/s |
| 4 Zettabits per second | 3725290298462 Gibit/s |
| 5 Zettabits per second | 4656612873077 Gibit/s |
| 10 Zettabits per second | 9313225746155 Gibit/s |
| 20 Zettabits per second | 18626451492310 Gibit/s |
| 25 Zettabits per second | 23283064365387 Gibit/s |
| 50 Zettabits per second | 46566128730774 Gibit/s |
| 100 Zettabits per second | 93132257461548 Gibit/s |
| Reference | Zettabits per second (Zbit/s) | Gibibits per second (Gibit/s) |
|---|---|---|
| A dial-up modem | 5.6 × 10-17 Zbit/s | 0.0000521541 Gibit/s |
| Typical home broadband | 1 × 10-13 Zbit/s | 0.0931323 Gibit/s |
| Gigabit Ethernet | 1 × 10-12 Zbit/s | 0.931323 Gibit/s |
| Streaming a 4K film | 2.5 × 10-14 Zbit/s | 0.0232831 Gibit/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 gibibit per second is a unit of data transfer rate equal to 1,073,741,824 bits per second. Its symbol is Gibit/s. It is the binary counterpart of the gigabit per second, and the two now differ by 7.4 per cent, which is enough to matter in any engineering specification.
The unit belongs to the inside of a machine rather than to the network. Memory buses, processor interconnects and the links between chips on the same board all move a power-of-two number of bits per clock cycle, so their throughput is naturally expressed with a binary prefix. A bus sixty-four bits wide clocked at a given frequency delivers a rate that is a binary multiple of that frequency.
Networking, by contrast, is decimal all the way down. Gigabit Ethernet carries exactly one thousand million bits per second, not 1,073,741,824, and the symbol rate on the wire is chosen to make that so. Confusing the two overstates a link's capacity by seven per cent, which in a capacity plan is the difference between adequate and insufficient.
In octets a gibibit per second is 134,217,728, or 128 mebioctets per second. That is close to the throughput of a fast mechanical hard drive and well below a modern solid-state drive, so it sits at the point where storage and internal buses meet and where matching their rates becomes a design question.
Benchmark tools are the commonest place to see the unit written correctly. A memory bandwidth test that allocates buffers in powers of two and measures how long they take to traverse naturally reports in gibibits or gibioctets per second, and a well-written tool says so explicitly rather than rounding to the decimal unit.
The reason to insist on the distinction here rather than lower down the scale is arithmetic. At the kibibit the gap was 2.4 per cent and could be ignored; here it is nearly a thirteenth, and it grows by a further 2.4 per cent at every step above. Getting into the habit at this level costs nothing and avoids compounding errors later.
One gibibit per second equals 1,073,741,824 bits per second, 134,217,728 octets per second, or about 1.074 gigabits per second.