How Many Zeros in a Zettabyte?
A zettabyte (ZB) has 21 zeros in the decimal system: 1,000,000,000,000,000,000,000 bytes, or 1021 bytes. One zettabyte equals 1,000 exabytes or one sextillion bytes. The binary equivalent — a zebibyte (ZiB) — equals 270 = 1,180,591,620,717,411,303,424 bytes, about 18.1% larger than the decimal zettabyte. The prefix "zetta-" is derived from a modified form of the Latin "septem" (seven), since zettabyte occupies the seventh position in the SI storage scale above a single byte. See also: Zeros in a gigabyte.
A zettabyte has
21
zeros
- Written Form
- 1 followed by 21 zeros bytes
- Scientific
- 10²¹ bytes
- Binary (IEC)
- 2⁷⁰ bytes (ZiB)
How Many Zeros Are in a Zettabyte?
In the decimal system, 1 ZB = 1,000,000,000,000,000,000,000 bytes — exactly 21 zeros following the leading 1. The exponent in 1021 tells you the count directly: 21 zeros, equal to one sextillion. The binary zebibyte (ZiB = 270) is not a round decimal number and carries no clean trailing-zero count. See also: How many zeros in a megabyte.
| Unit | Bytes | Zeros | Notation |
|---|---|---|---|
| Zettabyte (decimal, SI) | 1,000,000,000,000,000,000,000 | 21 | 1021 |
| Zebibyte (binary, IEC) | 1,180,591,620,717,411,303,424 | — | 270 |
Is a Zettabyte Bigger Than a Terabyte?
Yes — by an enormous margin. A zettabyte (1021 bytes, 21 zeros) is one billion times larger than a terabyte (1012 bytes, 12 zeros). The gap spans nine orders of magnitude: 1 ZB = 1,000,000,000 TB. To put that in perspective, a 1 TB hard drive — which holds roughly 500 hours of HD video — would need to be duplicated one billion times to reach a single zettabyte.
The storage hierarchy from terabyte to zettabyte shows three zeros added at each step:
| Unit | Zeros | Bytes |
|---|---|---|
| Terabyte (TB) | 12 | 1012 |
| Petabyte (PB) | 15 | 1015 |
| Exabyte (EB) | 18 | 1018 |
| Zettabyte (ZB) | 21 | 1021 |
Is a Zettabyte or Yottabyte Bigger?
A yottabyte is bigger. A zettabyte has 21 zeros (1021 bytes), while a yottabyte has 24 zeros (1024 bytes) — making a yottabyte exactly 1,000 times larger than a zettabyte. In other words, 1 YB = 1,000 ZB. The zettabyte sits one rung below the yottabyte in the SI storage scale, and three rungs above the exabyte.
The zettabyte has become the practical unit for describing global data volumes. IDC and other research firms project total worldwide data creation and replication in the tens of zettabytes per year — a figure that makes the zettabyte the most commonly referenced scale for "big data" discussions at a planetary level.