Gigabytes to Terabytes
A terabyte is one thousand gigabytes in decimal units, so divide gigabytes by 1,000 to get terabytes: 500 GB is 0.5 TB and 2,000 GB is 2 TB. In binary units a TiB is 1,024 GiB, which is why drives look smaller once they are plugged in.
1 gigabyte = 0.001 terabytes
1 GB = 0.001 TB · multiply by 0.001
Why a 1 TB drive shows 931 GB
Drive makers use decimal units: a 1 TB drive holds 1,000,000,000,000 bytes. Windows divides by 1,024 three times to reach gigabytes, so it shows 10¹² ÷ 1,073,741,824 = 931.3 GB, which is really 931.3 GiB. Nothing is missing; the operating system is counting in bigger steps and keeping the decimal labels.
The gap grows with each prefix: a reading in binary gigabytes is 6.9% lower than the decimal figure, and one in binary terabytes is 9.1% lower, so a 2 TB drive appears as about 1.82 TB, a 4 TB drive as 3.64 TB and an 8 TB drive as 7.28 TB. macOS has reported in decimal units since 2009, so the same drive shows its full 1 TB on a Mac, minus whatever the file system reserves.
Sizing backups and cloud storage
Add up what you need to keep in gigabytes, then convert. A phone backup of 120 GB, a photo library of 450 GB and a 300 GB music and document folder total 870 GB, or 0.87 TB, which fits on a 1 TB drive with almost no room to grow. Backup tools that keep old versions need extra space, so plan for one and a half to two times the raw total, a 2 TB drive in this case.
Cloud plans follow the same decimal arithmetic. Common tiers jump from 200 GB to 2 TB, so a library of 600 GB needs the larger plan. Moving large data by download is slow even on fast lines; 1 TB over a 500 Mbps connection takes at least 4.4 hours, which the megabits to MB page explains.
Gigabytes to terabytes at a glance
Seven values you meet most often. The tables and the converter handle everything in between.
- 1 GB0.001 TB
- 2 GB0.002 TB
- 5 GB0.005 TB
- 10 GB0.01 TB
- 20 GB0.02 TB
- 50 GB0.05 TB
- 100 GB0.1 TB
Gigabytes to terabytes conversion table
Rounded to six significant digits. Change any value in the converter above for an exact figure.
| Gigabytes (GB) | Terabytes (TB) |
|---|---|
| 1 | 0.001 |
| 2 | 0.002 |
| 3 | 0.003 |
| 4 | 0.004 |
| 5 | 0.005 |
| 6 | 0.006 |
| 7 | 0.007 |
| 8 | 0.008 |
| 9 | 0.009 |
| 10 | 0.01 |
| 12 | 0.012 |
| 15 | 0.015 |
| 20 | 0.02 |
| 25 | 0.025 |
| 30 | 0.03 |
| 40 | 0.04 |
| 50 | 0.05 |
| 60 | 0.06 |
| 70 | 0.07 |
| 75 | 0.075 |
| 80 | 0.08 |
| 90 | 0.09 |
| 100 | 0.1 |
| Terabytes (TB) | Gigabytes (GB) |
|---|---|
| 1 | 1,000 |
| 2 | 2,000 |
| 3 | 3,000 |
| 4 | 4,000 |
| 5 | 5,000 |
| 6 | 6,000 |
| 7 | 7,000 |
| 8 | 8,000 |
| 9 | 9,000 |
| 10 | 10,000 |
| 12 | 12,000 |
| 15 | 15,000 |
| 20 | 20,000 |
| 25 | 25,000 |
| 30 | 30,000 |
| 40 | 40,000 |
| 50 | 50,000 |
| 60 | 60,000 |
| 70 | 70,000 |
| 75 | 75,000 |
| 80 | 80,000 |
| 90 | 90,000 |
| 100 | 100,000 |
Beyond the terabyte
The next steps are the petabyte (1,000 TB) and the exabyte (1,000 PB); their binary partners are the pebibyte and exbibyte. For smaller figures go back to MB to GB, and the unit converter handles bits and bytes in every direction.
Frequently asked questions
- How many GB are in 1 TB?
- 1,000 GB in decimal units, which is how drives are sold. One tebibyte (TiB) is 1,024 GiB.
- Why does my 2 TB external drive show 1.81 TB?
- Windows divides 2,000,000,000,000 bytes by 1,024 four times, which gives about 1.82 TiB, and Explorer truncates it to 1.81 TB. The drive is full size.
- Is 512 GB half a terabyte?
- Close but not quite: 512 GB is 0.512 TB in decimal units. In binary units, 512 GiB is exactly half a TiB.
- How many 4K movies fit on 1 TB?
- A 4K film of 20 to 60 GB means roughly 16 to 50 films per terabyte, depending on bitrate and length.