How Many Zeros in a Yottabyte?
A yottabyte (YB) has 24 zeros in the decimal system: 1,000,000,000,000,000,000,000,000 bytes, or 1024 bytes. One yottabyte equals 1,000 zettabytes or one septillion bytes. The binary equivalent — a yobibyte (YiB) — equals 280 = 1,208,925,819,614,629,174,706,176 bytes, about 20.9% larger. The prefix "yotta-" derives from the Greek "okto" (eight), reflecting the yottabyte's position as the eighth SI storage unit above a single byte. From 1991 until November 2022, the yottabyte was the largest officially recognized SI storage prefix. See also: How many zeros in a gigabyte.
A yottabyte has
24
zeros
- Written Form
- 1 followed by 24 zeros bytes
- Scientific
- 10²⁴ bytes
- Binary (IEC)
- 2⁸⁰ bytes (YiB)
How Many Zeros Are in a Yottabyte?
In the decimal system, 1 YB = 1,000,000,000,000,000,000,000,000 bytes — exactly 24 zeros following the leading 1. The exponent in 1024 confirms this directly: 24 zeros, equivalent to one septillion. The binary yobibyte (YiB = 280) is not a round decimal figure and has no clean trailing-zero count. See also: Zeros in a petabyte.
| Unit | Bytes | Zeros | Notation |
|---|---|---|---|
| Yottabyte (decimal, SI) | 1,000,000,000,000,000,000,000,000 | 24 | 1024 |
| Yobibyte (binary, IEC) | 1,208,925,819,614,629,174,706,176 | — | 280 |
What Is the Number 1,208,925,819,614,629,174,706,176?
That specific figure is 280 — the yobibyte, the binary equivalent of a yottabyte as defined by the IEC (International Electrotechnical Commission). Unlike the decimal yottabyte (1024, a clean 1 followed by 24 zeros), the yobibyte is a power of 2 that doesn't resolve to a round decimal number. The 20.9% difference between 1024 and 280 is the largest gap between any SI and IEC storage unit pair up to this scale — because each step up compounds the rounding difference.
Is the Yottabyte the Largest Unit of Digital Storage?
No — though it held that distinction for over 30 years. In November 2022, the International Bureau of Weights and Measures (BIPM) officially added two larger SI storage units: the ronnabyte (RB, 1027 bytes, 27 zeros) and the quettabyte (QB, 1030 bytes, 30 zeros). These new prefixes were introduced to keep pace with the exponential growth of global data volumes, which were beginning to brush against the yottabyte scale. Before ronnabyte and quettabyte were named, data scientists sometimes used informal terms like "brontobyte" — but those were never official SI units.
For everyday purposes the yottabyte remains almost incomprehensibly large. The entire internet's estimated data volume was still measured in the low dozens of zettabytes as of the mid-2020s — still three orders of magnitude below a single yottabyte.