Terabytes to Zettabytes (TB to ZB)

1 terabyte equals 1×10⁻⁹ zettabytes exactly.

How to convert terabytes to zettabytes

To convert terabytes to zettabytes, multiply the number of terabytes by 1×10⁻⁹. This factor is exact. To go the other way, multiply zettabytes by 1,000,000,000.

zettabytes = terabytes × 1×10⁻⁹

Example: 10 terabytes = 1×10⁻⁸ zettabytes.

Decimal prefixes (kB, MB, GB) are powers of 1,000; binary prefixes (KiB, MiB, GiB) are powers of 1,024. Storage makers use decimal; Windows reports binary but labels it GB.

About these units

Terabyte (TB)

ComputingCurrent unit

1,000 gigabytes (10¹² bytes), the capacity of a typical modern hard drive.

Tera comes from the SI prefix for 10 to the twelfth, so a terabyte is one million million bytes. Computer memory is binary, so the prefixes were once used for powers of two, which caused confusion. IUPAC proposed binary prefixes such as kibi, mebi and gibi in 1995, and the IEC adopted them in December 1998 and published the standard in January 1999. The tebibyte is the binary counterpart, about 9 percent larger than the terabyte.

Hitachi introduced the first one-terabyte consumer hard drive in 2007. For scale, one terabyte is about 20 standard Blu-ray discs or 213 DVDs. The mismatch shows at this size: a drive sold as 1 TB may be reported as about 931 GB, because Windows uses the historic binary convention. macOS and iOS did the same until Mac OS X 10.5 Leopard and iOS 10, then switched to powers of 10.

1 terabyte = 1,000,000,000,000 bytes (exactly).

Sources: Wikipedia: Terabyte; Wikipedia: Binary prefix; NIST: Prefixes for binary multiples

Zettabyte (ZB)

ComputingCurrent unit

10²¹ bytes. Used for estimates of global data volumes.

Global data volumes are now large enough that the zettabyte, 10^21 bytes, has become a headline unit. It is decimal: 1,000 exabytes, or a trillion gigabytes, and the symbol is ZB. The prefix zetta was added to the SI in 1991 alongside yotta, and the binary counterpart is the zebibyte (ZiB), 2^70 bytes, which is about 18 percent larger.

Wikipedia's article on the Zettabyte Era puts the point when total digital data first passed one zettabyte at 2012. It also records Cisco's estimate that global IP network traffic first topped one zettabyte in 2016, at about 1.2 ZB, or roughly 96 exabytes a month. IDC forecasts quoted there projected annual data generation reaching 175 ZB by 2025, though such figures are estimates of data created rather than data kept, and they vary between analysts.

Almost nothing is stored in single zettabyte devices, so the unit matters mainly for industry totals.

1 zettabyte = 1×10²¹ bytes (exactly).

Sources: Wikipedia: Zettabyte Era; Wikipedia: Metric prefix; Wikipedia: Byte

Related conversions

See all digital storage units.