| Pebibits per second (Pibit/s) | Exabits per second (Ebit/s) |
|---|---|
| 1 Pebibit per second | 0.00112589990684 Ebit/s |
| 2 Pebibits per second | 0.00225179981369 Ebit/s |
| 3 Pebibits per second | 0.00337769972053 Ebit/s |
| 4 Pebibits per second | 0.00450359962737 Ebit/s |
| 5 Pebibits per second | 0.00562949953421 Ebit/s |
| 10 Pebibits per second | 0.0112589990684 Ebit/s |
| 20 Pebibits per second | 0.0225179981369 Ebit/s |
| 25 Pebibits per second | 0.0281474976711 Ebit/s |
| 50 Pebibits per second | 0.0562949953421 Ebit/s |
| 100 Pebibits per second | 0.112589990684 Ebit/s |
| Reference | Pebibits per second (Pibit/s) | Exabits per second (Ebit/s) |
|---|---|---|
| A dial-up modem | 4.9738 × 10-11 Pibit/s | 5.6 × 10-14 Ebit/s |
| Typical home broadband | 0.0000000888178 Pibit/s | 1 × 10-10 Ebit/s |
| Gigabit Ethernet | 0.000000888178 Pibit/s | 0.000000001 Ebit/s |
| Streaming a 4K film | 0.0000000222045 Pibit/s | 2.5 × 10-11 Ebit/s |
The pebibit per second is a unit of data transfer rate equal to 1,024 tebibits per second, which is two to the fiftieth power bits per second. Its symbol is Pibit/s. It is the binary counterpart of the petabit per second, and the two differ by 12.6 per cent.
No deployed system runs at this rate, and the unit therefore describes either an aggregate or a laboratory result. Optical transmission records set on single fibres reach a petabit per second, and the binary figure for the same experiment is 12.6 per cent lower — a difference that matters when comparing results between papers that use different conventions.
Where the unit is genuinely appropriate is in describing structures built from powers of two. The total switching capacity of a very large network fabric, built from ports and buffers that are all binary, is a binary quantity divided by time, and reporting it in decimal units discards the arithmetic that produced it. The same applies to the summed memory bandwidth of a machine whose channel count is a power of two.
In octets a pebibit per second is 140,737,488,355,328, which is 128 tebioctets per second. That is the storage of a thousand large consumer drives moved every second, and it exists only as a total across many thousands of parallel paths inside a single facility.
The size of the discrepancy at this level is the argument for the whole IEC series in miniature. What began as a harmless 2.4 per cent at the kibibit is now an eighth, and it compounds by 2.4 per cent at every further step. A convention that was acceptable for small numbers becomes untenable for large ones, and the point of the binary prefixes is to make the distinction visible before that happens.
For a converter, the arithmetic is unremarkable: multiply or divide by 1,024 the appropriate number of times, and by eight to reach octets. What matters is that the tool does not silently substitute the decimal unit when it sees a value it cannot label precisely.
One pebibit per second equals 1,024 tebibits per second, 140,737,488,355,328 octets per second, or about 1.126 petabits per second.
The exabit per second is a unit of data transfer rate equal to a thousand petabits per second. Its symbol is Ebit/s. No link, no cable and no exchange point runs at this rate; the unit describes the internet as a whole, or a large part of it, at a single instant.
Global internet traffic can be expressed this way. Worldwide traffic of several hundred exaoctets a month works out to roughly one exabit per second on average, and peak hours run higher. That figure is the sum of every packet moving on every network on the planet, and it is the only quantity anyone routinely describes at this scale.
An exabit per second is 125 petaoctets per second. Nothing generates data at that rate in one place; the number is an aggregate of billions of separate flows, most of them tiny. A single video stream is a few megabits per second, so an exabit per second is on the order of a hundred million such streams running at once.
The composition of that traffic is dominated by video. Streaming services account for the largest share, followed by social platforms, software updates and cloud synchronisation. Ordinary web browsing and messaging, which people think of as the internet, are a small fraction of the total by volume even though they occupy most of the attention.
The unit also appears in projections of aggregate capacity. The total installed capacity of all submarine cables, if every wavelength on every fibre pair were lit and used simultaneously, is in the exabit-per-second range. Actual utilisation is far below that, because capacity is built ahead of demand and because routes must carry each other's traffic when a cable fails.
The prefix exa is a thousand to the sixth power. It was adopted in 1975, when nobody expected it to describe anything but astronomical quantities, and it now describes the working throughput of a communications system built by human beings. The interval between definition and everyday use was about forty years.
One exabit per second equals 1,000 petabits per second, 125 petaoctets per second, or about 0.8674 exbibits per second.