| Mebibits per second (Mibit/s) | Exbioctets per second (Eio/s) |
|---|---|
| 1 Mebibit per second | 1.13686837722 × 10-13 Eio/s |
| 2 Mebibits per second | 2.27373675443 × 10-13 Eio/s |
| 3 Mebibits per second | 3.41060513165 × 10-13 Eio/s |
| 4 Mebibits per second | 4.54747350886 × 10-13 Eio/s |
| 5 Mebibits per second | 5.68434188608 × 10-13 Eio/s |
| 10 Mebibits per second | 1.13686837722 × 10-12 Eio/s |
| 20 Mebibits per second | 2.27373675443 × 10-12 Eio/s |
| 25 Mebibits per second | 2.84217094304 × 10-12 Eio/s |
| 50 Mebibits per second | 5.68434188608 × 10-12 Eio/s |
| 100 Mebibits per second | 1.13686837722 × 10-11 Eio/s |
| Reference | Mebibits per second (Mibit/s) | Exbioctets per second (Eio/s) |
|---|---|---|
| A dial-up modem | 0.0534058 Mibit/s | 6.07153 × 10-15 Eio/s |
| Typical home broadband | 95.3674 Mibit/s | 1.0842 × 10-11 Eio/s |
| Gigabit Ethernet | 953.674 Mibit/s | 1.0842 × 10-10 Eio/s |
| Streaming a 4K film | 23.8419 Mibit/s | 2.71051 × 10-12 Eio/s |
The mebibit per second is a unit of data transfer rate equal to 1,048,576 bits per second. Its symbol is Mibit/s. It is the binary counterpart of the megabit per second, and the two differ by 4.9 per cent — small, but large enough to change a headline figure.
That five per cent is where the unit starts to matter. A connection advertised at 100 megabits per second and a connection at 100 mebibits per second differ by about five megabits, which is a whole high-definition video stream. In a specification, a contract or a benchmark report, quoting one and delivering the other is a real discrepancy rather than a rounding difference.
In practice the confusion is rare in networking, because network equipment is always specified in decimal. What produces mebibit figures is measurement software: a tool that counts a transfer in mebioctets and divides by elapsed seconds is reporting a binary rate, and multiplying by eight makes it mebibits per second. A person comparing that reading with an advertised rate must convert twice, once for the base and once for the factor of eight.
Where a genuine binary rate does arise is inside a machine. A memory bus transfers a fixed number of bits per clock cycle, and the width is a power of two — sixty-four bits at a time, for instance — so the quantity moved per cycle is binary even though the clock frequency is not. Rates derived from such a structure are naturally expressed with binary prefixes.
For scale, a mebibit per second is 131,072 octets per second, or about 128 kibioctets per second. That is roughly a photograph every two seconds, or a plain-text novel every four. It is a rate at which the modern web is slow but usable, which puts it in the range that mobile networks fall to when congested.
The correct symbol has the lowercase i, and its presence is the only reliable way to tell the two conventions apart. A document writing Mbit/s in a context where the underlying figure came from a binary computation has misstated its own measurement by five per cent.
One mebibit per second equals 1,048,576 bits per second, 131,072 octets per second, or about 1.049 megabits 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.