Counts stored bytes in powers of 1,024. The quantity is 2^40 bytes, which is 1,099,511,627,776 bytes, the same as 1,024 Gibibyte (GiB).
Memory reports and disk tools use that step when they scale from one binary size to the next. A decimal Terabyte (TB) counts powers of 1,000 instead, so the two labels name different amounts of storage.
Binary Prefix for 2^40
The prefix tebi, symbol Ti, is the binary prefix for 2^40. IEC 80000-13 names the binary prefixes kibi, mebi, gibi, tebi, pebi, exbi, zebi, yobi, robi, and quebi so they are not confused with SI decimal prefixes. Tebi is 1,024 multiplied by itself four times, and that product is the same 1,099,511,627,776 bytes.
- Tebi. Marks 2^40 and pairs with the symbol Ti.
- Gibi. The binary name one factor of 1,024 lower, at 2^30 bytes.
- The rest of the list. Kibi, mebi, pebi, exbi, zebi, yobi, robi, and quebi give the other binary steps their own names.
Where the Decimal Count Differs
A decimal terabyte is 10^12 bytes, or 1,000,000,000,000 bytes. That amount is about 9.1 percent smaller than a tebibyte. The gibibyte under the tebibyte is 2^30 bytes, and 1,024 gibibytes make one tebibyte. Dividing 1,099,511,627,776 by 1,024 gives 1,073,741,824 bytes for that smaller binary unit.
A Gigabyte (GB) is the decimal unit one step under a terabyte. Dividing 1,000,000,000,000 by 1,000 gives 1,000,000,000 bytes.
| Unit | Bytes | Relation |
| Tebibyte | 1,099,511,627,776 | 2^40, equal to 1,024 gibibytes |
| Terabyte | 1,000,000,000,000 | 10^12, about 9.1 percent smaller than a tebibyte |
| Gibibyte | 1,073,741,824 | 2^30, and 1,024 of these equal one tebibyte |
| Gigabyte | 1,000,000,000 | One thousandth of the terabyte count |
