| Tebibits per second (Tibit/s) | Yottabits per second (Ybit/s) |
|---|---|
| 1 Tebibit per second | 1.09951162778 × 10-12 Ybit/s |
| 2 Tebibits per second | 2.19902325555 × 10-12 Ybit/s |
| 3 Tebibits per second | 3.29853488333 × 10-12 Ybit/s |
| 4 Tebibits per second | 4.3980465111 × 10-12 Ybit/s |
| 5 Tebibits per second | 5.49755813888 × 10-12 Ybit/s |
| 10 Tebibits per second | 1.09951162778 × 10-11 Ybit/s |
| 20 Tebibits per second | 2.19902325555 × 10-11 Ybit/s |
| 25 Tebibits per second | 2.74877906944 × 10-11 Ybit/s |
| 50 Tebibits per second | 5.49755813888 × 10-11 Ybit/s |
| 100 Tebibits per second | 1.09951162778 × 10-10 Ybit/s |
| Reference | Tebibits per second (Tibit/s) | Yottabits per second (Ybit/s) |
|---|---|---|
| A dial-up modem | 0.0000000509317 Tibit/s | 5.6 × 10-20 Ybit/s |
| Typical home broadband | 0.0000909495 Tibit/s | 1 × 10-16 Ybit/s |
| Gigabit Ethernet | 0.000909495 Tibit/s | 1 × 10-15 Ybit/s |
| Streaming a 4K film | 0.0000227374 Tibit/s | 2.5 × 10-17 Ybit/s |
The tebibit per second is a unit of data transfer rate equal to 1,099,511,627,776 bits per second, which is 1,024 gibibits per second. Its symbol is Tibit/s. It is the binary counterpart of the terabit per second, and the two differ by 10 per cent.
Ten per cent is the point at which the distinction becomes a matter of money rather than of pedantry. A supplier quoting a system at a hundred terabits per second and a customer measuring a hundred tebibits per second are not describing the same performance, and the difference is ten terabits — more than most organisations' entire external connectivity.
The rate belongs to the interior of very large machines. The aggregate memory bandwidth of a rack of accelerators, or the internal switching capacity of a large network chip, reaches this range, and both are built from power-of-two structures: memory channels of fixed binary width, switch ports in powers of two, buffers sized in binary. Expressing their totals with binary prefixes preserves the arithmetic that produced them.
In octets a tebibit per second is 137,438,953,472, or 128 gibioctets per second. That is more than any single storage device can supply and more than any external cable carries. It is a figure that describes something happening inside a cabinet, between chips connected by short traces on a board, where the physical distance is measured in centimetres.
Optical research also brushes this range. A laboratory demonstration carrying a petabit per second down one fibre is a thousand times higher, but individual wavelength channels and the electronics driving them work at tebibit-scale aggregates, and papers reporting them often state the binary figure because the underlying frame sizes are binary.
The habit of writing the lowercase i is worth keeping even where the reader is unlikely to check. A number written unambiguously can be converted correctly by anyone who reads it later; one written ambiguously cannot be repaired, and at ten per cent the ambiguity is no longer harmless.
One tebibit per second equals 1,024 gibibits per second, 137,438,953,472 octets per second, or about 1.100 terabits per second.
The yottabit per second is a unit of data transfer rate equal to a thousand zettabits per second. Its symbol is Ybit/s. For thirty years it was the largest rate the metric system could name, and it describes a speed that has no application anywhere: not in engineering, not in research, and not in any forecast that anyone takes seriously.
Its distance from reality is easy to state. Global internet traffic averages roughly one exabit per second, so a yottabit per second is about a million times the combined communication of the entire human species. The largest single link ever built runs at a few hundred terabits per second, which is a ten-billionth of this figure.
The unit is nonetheless properly defined, and that completeness is the point. The metric system's rule is that every prefix combines with every unit without exception, so a reader who has never seen Ybit/s can decode it from the prefix alone. A system with gaps would need a table of which combinations are legal, and a table is exactly what a rule-based system exists to avoid.
There is a physical way to think about the number. A yottabit per second is 125 zettaoctets per second, and the total quantity of data humanity has ever stored is a few hundred zettaoctets. A link at this rate would therefore transmit the entire accumulated information of the species in a couple of seconds. No such body of data exists in one place to be sent, and nothing at the far end could receive it.
The prefix yotta was adopted in 1991 alongside zetta, at a conference that also had to consider which letters remained free. It stood at the top of the metric ladder until 2022, when ronna and quetta were added above it, partly because data quantities were beginning to approach the old ceiling. Rates have not followed quantities upward at the same pace.
For a converter, handling the unit is a matter of consistency rather than utility. A tool that converts every metric prefix correctly does not need to decide which of them anyone will use, and a figure written in yottabits per second — however unlikely — converts by the same rule as any other.
One yottabit per second equals 1,000 zettabits per second, 125 zettaoctets per second, or about 0.8272 yobibits per second.