Tebibytes to terabytes (TiB to TB)

One tebibyte is exactly 1.099511628 terabytes. That is the definition of the prefixes, not a measurement: the decimal SI prefixes (kilo, mega, giga, tera) step by exactly 1,000, and the binary IEC prefixes (kibi, mebi, gibi, tebi) step by exactly 1,024. The two families are both exact; the trouble is only that software and storage labels do not always say which one they mean.

Worked through: 10 TiB x 1.09951163 = 10.9951 TB.

Going the other way, one terabyte is 0.9094947018 tebibytes.

For mental arithmetic: Multiply by 1.1, or add 10%.

A tebibyte is 2^40 bytes, 1,099,511,627,776, so it is about 10% larger than a decimal terabyte, and this is the gap that turns a drive's label into a smaller pool. Storage systems such as ZFS and TrueNAS report capacity in TiB, while the drives inside them are sold in TB: eight 4 TB drives are 32 TB, which is 29.1 TiB before any space goes to parity. The 10% is not lost to formatting; it is the same bytes counted in a larger unit.

Precision is worth matching to the input. A measurement given as 1 TiB carries one or two significant figures, and reporting its conversion to six implies a precision the original never had.