A quettabyte (QB) is a unit of digital information equal to 1030 bytes—a 1 followed by 30 zeros. In short-scale naming, this is one nonillion bytes.
How a quettabyte compares to other units
| Unit | Size in bytes | Relation to 1 quettabyte |
|---|---|---|
| Terabyte (TB) | 1012 | 1018 TB = 1 QB |
| Petabyte (PB) | 1015 | 1015 PB = 1 QB |
| Exabyte (EB) | 1018 | 1012 EB = 1 QB |
| Zettabyte (ZB) | 1021 | 109 ZB = 1 QB |
| Yottabyte (YB) | 1024 | 106 YB = 1 QB |
| Ronnabyte (RB) | 1027 | 103 RB = 1 QB |
| Quettabyte (QB) | 1030 | — |
Why the prefix “quetta” exists
In 2022, the International System of Units (SI) introduced the prefix quetta- (Q) to represent 1030. It was added to handle extremely large quantities, such as future global data volumes, beyond the older maximum prefix yotta- (1024).
How big is a quettabyte?
A quettabyte is so large that no existing storage system can hold that much data. It is mainly a forward-looking concept for describing possible future data scales. For a rough sense of scale: even if every grain of sand on Earth were one byte, you would still need many Earths’ worth of sand to reach a quettabyte.
Binary counterpart: qubibyte
In binary (base 2), the approximate counterpart is the qubibyte (QiB). One qubibyte is defined as 2100 bytes, which is about 1.27 × 1030 bytes—slightly larger than a quettabyte.
Why it matters
Even though we do not yet store data at the scale of quettabytes, the term is useful for planning and describing future data growth in areas like artificial intelligence, the Internet of Things, and large scientific simulations.
What comes after quetta?
As of now, quetta- is the largest official SI prefix. Its very small counterpart is quecto- (q), which represents 10-30.