Tebibyte

The tebibyte (symbol TiB) is a binary unit of measurement for digital information equal to 2 to the 40th power bytes, or 1,099,511,627,776 bytes. It is part of the binary system of data measurement developed to distinguish from the decimal-based terabyte (TB) used in many storage device specifications. One tibibyte comprises 1024 gibibytes (GiB), 1,048,576 mebibytes (MiB), 1,073,741,824 kibibytes (KiB), and 1,099,511,627,776 kibibytes. In binary terms, 1 TiB equals 8,796,093,022,208 bits.

The unit was introduced by the International Electrotechnical Commission in 1998 to provide a consistent metric for computer hardware and data storage, and later adopted by the International System of Units (SI) and the International Organization for Standardization (ISO) in 1998 and 2005 respectively. The prefix “tebi‑” comes from “binary” tebi, which is a combination of Latin “bi” (two) and Greek “mega” for million, analogous to the SI prefix tera-, which denotes ten to the twelve power. The use of binary prefixes such as kibi‑, mebi‑, gibi‑, and tebi‑ was promoted to reduce ambiguity between binary and decimal measurements in computing.

In practice, tebibytes are commonly used when describing the capacity of file systems, hard disk drives, solid‑state drives, and cloud storage in technical documentation. Many operating systems report disk sizes in tebibytes because the file system only interprets data in powers of two. Ordinary consumers, however, often see terabytes when purchasing storage devices, which can lead to confusion because the decimal TB is roughly 1.1 times a TiB.

See also: binary prefix, tebibyte, terabyte, gibibyte, mebibyte, kibibyte.