| Exbibits per second (Eibit/s) | Mebibits per second (Mibit/s) |
|---|---|
| 1 Exbibit per second | 1099511627776 Mibit/s |
| 2 Exbibits per second | 2199023255552 Mibit/s |
| 3 Exbibits per second | 3298534883328 Mibit/s |
| 4 Exbibits per second | 4398046511104 Mibit/s |
| 5 Exbibits per second | 5497558138880 Mibit/s |
| 10 Exbibits per second | 10995116277760 Mibit/s |
| 20 Exbibits per second | 21990232555520 Mibit/s |
| 25 Exbibits per second | 27487790694400 Mibit/s |
| 50 Exbibits per second | 54975581388800 Mibit/s |
| 100 Exbibits per second | 109951162777600 Mibit/s |
| Reference | Exbibits per second (Eibit/s) | Mebibits per second (Mibit/s) |
|---|---|---|
| A dial-up modem | 4.85723 × 10-14 Eibit/s | 0.0534058 Mibit/s |
| Typical home broadband | 8.67362 × 10-11 Eibit/s | 95.3674 Mibit/s |
| Gigabit Ethernet | 8.67362 × 10-10 Eibit/s | 953.674 Mibit/s |
| Streaming a 4K film | 2.1684 × 10-11 Eibit/s | 23.8419 Mibit/s |
The exbibit per second is a unit of data transfer rate equal to two to the sixtieth power bits per second, which is 1,024 pebibits per second. Its symbol is Eibit/s. It is the binary counterpart of the exabit per second, and the two differ by 15.3 per cent.
That fifteen per cent is more than the margin most engineering work allows anywhere. A quantity stated in the wrong convention at this level is not slightly imprecise but plainly wrong, and no amount of context recovers the intended figure once it has been written ambiguously. This is the situation the IEC prefixes were introduced to prevent.
No physical link approaches this rate. The unit describes aggregates: the total instantaneous traffic of the whole internet is roughly an exabit per second, so a binary exbibit per second is fifteen per cent more than everything moving on every network on the planet at a given moment.
Where a binary figure of this size arises naturally is in address arithmetic rather than in transmission. Two to the sixtieth is a number that appears throughout the design of 64-bit systems, and any rate derived from filling or traversing such an address space in a fixed time is naturally binary. Those calculations are theoretical, but they are the reason the unit is defined rather than left unnamed.
In octets an exbibit per second is 144,115,188,075,855,872, or 128 pebioctets per second. That is more storage moved per second than the world manufactures in several years, which is a way of saying that no source and no destination for such a flow could exist.
For a converter the treatment is mechanical and must be exact. Eibit/s and Ebit/s differ by an eighth, and a tool that treats them as interchangeable has introduced an error larger than the difference between many neighbouring units. The lowercase i is not decoration.
One exbibit per second equals 1,024 pebibits per second, 144,115,188,075,855,872 octets per second, or about 1.153 exabits per second.
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.