| Kibibits per second (Kibit/s) | Exbioctets per second (Eio/s) |
|---|---|
| 1 Kibibit per second | 1.11022302463 × 10-16 Eio/s |
| 2 Kibibits per second | 2.22044604925 × 10-16 Eio/s |
| 3 Kibibits per second | 3.33066907388 × 10-16 Eio/s |
| 4 Kibibits per second | 4.4408920985 × 10-16 Eio/s |
| 5 Kibibits per second | 5.55111512313 × 10-16 Eio/s |
| 10 Kibibits per second | 1.11022302463 × 10-15 Eio/s |
| 20 Kibibits per second | 2.22044604925 × 10-15 Eio/s |
| 25 Kibibits per second | 2.77555756156 × 10-15 Eio/s |
| 50 Kibibits per second | 5.55111512313 × 10-15 Eio/s |
| 100 Kibibits per second | 1.11022302463 × 10-14 Eio/s |
| Reference | Kibibits per second (Kibit/s) | Exbioctets per second (Eio/s) |
|---|---|---|
| A dial-up modem | 54.6875 Kibit/s | 6.07153 × 10-15 Eio/s |
| Typical home broadband | 97656.2 Kibit/s | 1.0842 × 10-11 Eio/s |
| Gigabit Ethernet | 976562 Kibit/s | 1.0842 × 10-10 Eio/s |
| Streaming a 4K film | 24414.1 Kibit/s | 2.71051 × 10-12 Eio/s |
The kibibit per second is a unit of data transfer rate equal to 1,024 bits per second. Its symbol is Kibit/s. It is the binary counterpart of the kilobit per second, and it is the least used member of an already unusual family, because transfer rates are one of the few places in computing where the decimal convention has always been unambiguous.
Networking has counted in true thousands from the beginning. A modem rated at 56 kilobits per second meant fifty-six thousand, not fifty-seven thousand three hundred and forty-four. The reason is that a transmission rate is set by a clock, and clocks are specified in decimal frequencies: a link running at ten million symbols per second carries a decimal number of bits, not a power of two.
The binary prefixes exist for quantities, not for rates, because quantities of storage are organised in powers of two while time is not. There is no natural reason for a rate to be a power of two, and consequently no reason for a rate unit to need a binary prefix. Where one appears, it is almost always because a program divided a binary file size by a duration.
That is exactly where the kibibit per second does turn up. A tool that measures a transfer by counting kibioctets and dividing by seconds produces a rate in kibioctets per second, and multiplying by eight gives kibibits per second. The unit is a consequence of the arithmetic rather than a description of the channel.
For scale, a kibibit per second is 128 octets per second, and the difference from a kilobit per second is 2.4 per cent — smaller than the measurement error of almost any real throughput test. At this level the distinction is technically correct and practically invisible, which is a fair description of the whole binary prefix system at its lower end.
The unit is properly defined and a converter must handle it, because the IEC series applies to every unit without exception. Whether anyone writes it is a separate question from whether it means something definite, and it does.
One kibibit per second equals 1,024 bits per second, 128 octets per second, or 1.024 kilobits per second.
The exbioctet per second is a unit of data transfer rate equal to 1,024 pebioctets per second, or two to the sixtieth power octets per second. Its symbol is Eio/s. It is the binary counterpart of the exaoctet per second, and the two differ by 15.3 per cent.
No machine, network or aggregate reaches this rate. An exbioctet per second is more than eight times the total instantaneous traffic of the entire internet, and it would move the world's whole stock of stored data in a matter of minutes. The unit describes a capacity with no source that could supply it and no destination that could take it in.
Two to the sixtieth is nevertheless a familiar number in computing, because it is the size of the address space a 64-bit machine can reach in octets divided by sixteen. The same power of two turns up in filesystem limits, in memory maps and in the design of every system built on that architecture, so the quantity is well known even though no rate approaches it.
The unit exists because the IEC series was defined completely. Every binary prefix pairs with every unit, exactly as every metric prefix does, so that a reader who has never seen Eio/s can decode it from the prefix alone. A system with gaps would need a table of permitted combinations, which is precisely what a rule-based system exists to avoid.
The difference from the decimal unit is worth restating at each level because it compounds. At the kibioctet it was 2.4 per cent, here it is more than an eighth, and at the yobioctet it will be more than a fifth. That growth is the reason the binary prefixes were created, and it is why the lowercase i has to be written even in figures nobody will check.
For a converter, the treatment is mechanical: six multiplications by 1,024 from octets, or the equivalent divisions coming down. The value of doing it correctly is not that anyone will use the result, but that a tool which handles every case the same way can be trusted on the cases that matter.
One exbioctet per second equals 1,024 pebioctets per second, 1,152,921,504,606,846,976 octets per second, or about 1.153 exaoctets per second.