Prefixes for bit and byte multiples
Decimal Value SI 1000 k kilo 10002 M mega 10003 G giga 10004 T tera 10005 P peta 10006 E exa 10007 Z zetta 10008 Y yotta	Binary Value IEC JEDEC 1024 Ki kibi K kilo 10242 Mi mebi M mega 10243 Gi gibi G giga 10244 Ti tebi 10245 Pi pebi 10246 Ei exbi 10247 Zi zebi 10248 Yi yobi

A zettabyte (symbol ZB, derived from the SI prefix zetta-) is a unit of information or computer storage equal to one sextillion (one long scale trilliard) bytes.^[1][2][3][4]

• 1,000,000,000,000,000,000,000 bytes = 1000⁷, or 10²¹.

The term "zebibyte" (ZiB), using a binary prefix, is used for the corresponding multiple of 1024.

[edit] Comparisons for scale

A zettabyte is equal to 1 billion terabytes.

According to IDC, as of 2006 the total amount of digital data in existence was 0.161 zettabytes; the same paper estimates that by 2010, the rate of digital data generated worldwide will be 0.988 zettabytes per year,^[5] which, according to Google's CEO Eric Schmidt was already reached in 2009.^[6]

Mark Liberman calculated the storage requirements for all human speech ever spoken at 42 zettabytes, if digitized as 16 kHz 16-bit audio. This was done in response to a popular expression that states "all words ever spoken by human beings" could be stored in approximately 5 exabytes of data (see exabyte for details). Liberman did "freely confess that maybe the authors [of the exabyte estimate] were thinking about text."^[7]

[edit] See also

• Binary prefix
• Orders of magnitude (data)

[edit] References

v • d • e Units of information Base units Bit · Byte Related units Nibble · Word · Octet Traditional units Kilobyte · Megabyte · Gigabyte · Terabyte · Petabyte · Exabyte · Zettabyte · Yottabyte IEC standard units Kibibyte · Mebibyte · Gibibyte · Tebibyte · Pebibyte · Exbibyte · Zebibyte · Yobibyte Bit-based units Kilobit · Megabit · Gigabit · Terabit · Petabit · Exabit · Zettabit · Yottabit