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How Many Zeros

How Many Zeros in a Yottabyte?

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. From 1991 until November 2022, the yottabyte was the largest officially recognized SI storage prefix. See also: How many zeros does a gigabyte have.

A yottabyte has

24

zeros

Written Form
1 followed by 24 zeros bytes
Scientific
10²⁴ bytes
Binary (IEC)
2⁸⁰ bytes (YiB)

Verifying the Zero Count in a Yottabyte

The direct answer: exactly 24 zeros, equivalent to one septillion. The prefix "yotta-" derives from the Greek okto (eight), reflecting its position as the eighth SI storage unit above a single byte. See also: How many zeros in a zettabyte.

How many zeros in a Yottabyte? 24 zeros, written as 1 followed by 24 zeros bytes (10²⁴ bytes).
How many zeros in a Yottabyte? — howmanyzeros.org
SI decimal yottabyte vs IEC binary yobibyte.
UnitBytesZerosNotation
Yottabyte (decimal, SI)1,000,000,000,000,000,000,000,000241024
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 figure is 280 — the yobibyte. Unlike the decimal yottabyte, a clean 1 followed by 24 zeros, the yobibyte is a power of 2 that doesn't resolve to a round decimal number — a 20.9% gap, the largest between any SI and IEC storage pair up to this scale.

Why the Yottabyte Held the Record for 30 Years

  • Named in 1991, well ahead of any real-world need for it
  • Global data volumes only reached low zettabytes by the mid-2020s
  • No SI update was needed until data growth projections demanded headroom

Is the Yottabyte the Largest Unit of Digital Storage?

No — though it held that distinction for over 30 years. In November 2022, the BIPM officially added two larger SI storage units: the ronnabyte (1027 bytes) and the quettabyte (1030 bytes). Related: How many zeros does a byte have.

  • Yottabyte (YB) — 1024, 24 zeros
  • Ronnabyte (RB) — 1027, 27 zeros
  • Quettabyte (QB) — 1030, 30 zeros

Before ronnabyte and quettabyte were named, data scientists sometimes used the informal term "brontobyte" — but it was never an official SI unit.

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, three orders of magnitude below a single yottabyte.

Zeros in a Yottabyte: FAQ

What comes before a yottabyte?
Quick answer

Zettabyte comes right before yottabyte — a yottabyte is exactly 1,000 zettabytes.

What comes after a yottabyte?
Quick answer

Ronnabyte comes next, followed by quettabyte.

How many digits does a yottabyte have?

A yottabyte has 25 digits in total — that's the digit 1 followed by 24 zeros.

Is a yottabyte the same as a septillion bytes?

Yes — a decimal yottabyte (1024 bytes) is exactly one septillion bytes.

What was "brontobyte"?

An informal, never-official term some data scientists used before ronnabyte and quettabyte were formally ratified in 2022.

How many yottabytes are in a ronnabyte?

Exactly 1,000 yottabytes make one ronnabyte.