Digital storage · drive capacity
TB to TiB converter.
Enter the capacity printed on the drive to see the TiB and the GiB figure an operating system that counts in binary will report.
Inputs
What the OS shows
Enter the numbers above.
TB to TiB: where the missing space goes
Drive makers use SI units, so 1 TB is 10^12 bytes. A tebibyte (TiB) is 2^40 bytes, 1,099,511,627,776, so 1 TB is 1 / 1.0995 = 0.9095 TiB. Windows, Wikipedia notes, still uses the labels MB and GB for binary multiples, so a 1 TB drive appears as roughly 931 "GB". Nothing is missing: the same bytes are counted with a larger unit. Formatting, recovery partitions and file-system structures then take a little more.
Worked example. 1 TB = 1,000,000,000,000 bytes / 1,073,741,824 = 931.32 GiB = 0.9095 TiB, an apparent shortfall of 6.87 percent. A 2 TB drive shows 1,862.65 GiB and a 500 GB drive shows 465.66 GiB. The gap grows with the prefix: about 2.4 percent at kilo, 4.6 percent at mega, 6.9 percent at giga and 9.1 percent at tera.
Frequently asked questions
How many TiB is 1 TB?
1 TB is 0.9095 TiB, because 10^12 bytes divided by 2^40 bytes is 0.90949.
Why does my 1 TB drive show 931 GB?
The drive holds 10^12 bytes. Windows counts in units of 1,073,741,824 bytes (a GiB) but labels them GB, so 10^12 bytes appears as 931 GB.
How many TB is 1 TiB?
1 TiB is 1.0995 TB, since 2^40 bytes is 1,099,511,627,776 bytes.
Do all operating systems show 931 GB?
No. Wikipedia notes Windows still uses MB and GB for binary multiples, while Mac OS X, Ubuntu and Debian were updated to show decimal units, so the same drive can look different on each.
Sources
Checked
- NIST, "Prefixes for binary multiples", opened 15 October 2026. kibi, mebi, gibi, tebi are 2^10, 2^20, 2^30, 2^40; under SI mega means 1,000,000, so 1 MB = 10^6 bytes and 1 GB = 10^9 bytes
- Wikipedia, "Binary prefix", opened 15 October 2026. Windows still uses "MB" and "GB" for binary multiples when showing drive capacities (a 300 GB drive reported as 279.4 GB, a "1 TB" drive as 931 GB), while Mac OS X, Ubuntu and Debian were updated to show decimal
Runs entirely in your browser. Nothing you type is sent or stored.
Scope
Unit arithmetic only. Real usable space is lower still after formatting, reserved partitions and file-system overhead, which vary by device and system.