TB to GB Converter
Type terabytes to get gigabytes, plus the size your operating system will report for a drive sold as that many terabytes.
2 TB =
2,000GB
2 terabytes is 2,000 gigabytes.
- Shown by Windows as
- 1.819 “TB”
- 1 TB
- 1,000 GB
- 1 GB
- 0.001 TB
How to convert TB to GB
Multiply terabytes by 1,000. Drive makers use the SI definition, so a 4 TB hard disk holds 4,000 GB, which is 4,000,000,000,000 bytes.
Plug that disk into a Windows PC and it shows about 3.64 TB. Nothing is missing: Windows divides the bytes by 1,024 four times and calls the result TB, when it is really tebibytes. 4 × 10¹² ÷ 1,024⁴ = 3.638 TiB, or 3,725.29 GiB.
For the same reason a 2 TB drive appears as 1.82 TB and a 1 TB drive as 931 GB. Formatting takes a little more for the file system, but most of the gap is just the two ways of counting.
gigabytes = terabytes × 1,000
- A terabyte (TB) is 10¹² bytes; a tebibyte (TiB) is 2⁴⁰ = 1,099,511,627,776 bytes, which is why a drive’s size shrinks when shown in binary units. Source: NIST, Prefixes for binary multiples (IEC 80000-13).
How to estimate TB to GB in your head
For decimal units add three zeros: 6 TB is 6,000 GB. To predict what Windows will report for a new drive, take off about 9%: 10 TB shows as roughly 9.1 TB (the precise figure is 9.095).
The shortfall grows with each prefix step. Kilobytes differ by 2.4%, megabytes by 4.6%, gigabytes by 6.9% and terabytes by 9.1%, so the bigger the drive, the more it seems to shrink when you plug it in.
Terabytes to gigabytes chart
Drive sizes as sold, in decimal GB, and the size Windows reports (binary units, labelled TB and GB).
| Drive size (TB) | Gigabytes (× 1000) | Windows shows (TiB) | Windows shows (GiB) |
|---|---|---|---|
| 0.25 | 250 | 0.2274 | 232.831 |
| 0.5 | 500 | 0.4547 | 465.661 |
| 1 | 1,000 | 0.9095 | 931.323 |
| 1.5 | 1,500 | 1.3642 | 1,396.98 |
| 2 | 2,000 | 1.819 | 1,862.65 |
| 3 | 3,000 | 2.7285 | 2,793.97 |
| 4 | 4,000 | 3.638 | 3,725.29 |
| 5 | 5,000 | 4.5475 | 4,656.61 |
| 6 | 6,000 | 5.457 | 5,587.94 |
| 8 | 8,000 | 7.276 | 7,450.58 |
Show all 17 rowsShow fewer
| 10 | 10,000 | 9.0949 | 9,313.23 |
| 12 | 12,000 | 10.9139 | 11,175.9 |
| 14 | 14,000 | 12.7329 | 13,038.5 |
| 16 | 16,000 | 14.5519 | 14,901.2 |
| 18 | 18,000 | 16.3709 | 16,763.8 |
| 20 | 20,000 | 18.1899 | 18,626.5 |
| 24 | 24,000 | 21.8279 | 22,351.7 |
Frequently Asked Questions
Why does my 2 TB drive show 1.81 TB?
2 TB is 2,000,000,000,000 bytes. Windows divides by 1,024⁴ and gets 1.819, which it labels “TB”. The drive is the full size; the operating system is using binary tebibytes.
How many GB is 1 TB?
1 TB is 1,000 GB. Measured in binary units, a 1 TB drive is 931.32 GiB.
Does macOS show the same size?
No. Since Mac OS X 10.6, Finder reports sizes in decimal units, so a 2 TB drive shows as about 2 TB there, minus file system overhead.