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GB to TB Converter

Convert gigabytes to terabytes instantly, and see why a 1 TB drive never shows 1 TB of free space.

GB to TB Converter

1 GB = 0.001 TB

Multiply gigabytes by 0.001 to get terabytes.

The link carries the values you entered, so whoever opens it sees the same result. Nothing is stored on our side — the numbers travel in the link itself.

Gigabytes to terabytes reference table

The conversions people look up most often, rounded to 5 decimal places.

Common gigabytes to terabytes conversions
Gigabyte (GB)Terabyte (TB)
100 GB0.1 TB
250 GB0.25 TB
500 GB0.5 TB
931 GB0.931 TB
1,000 GB1 TB
1,024 GB1.024 TB
2,000 GB2 TB
4,000 GB4 TB
8,000 GB8 TB
12,000 GB12 TB
16,000 GB16 TB

The gigabytes people look up most

500 GB = 0.5 TB
The smallest SSD worth fitting in a machine you actually work on.
931 GB = 0.931 TB
The figure Windows shows for a drive sold as a terabyte. Nothing is missing - the shortfall is the binary convention.
1,000 GB = 1 TB
One terabyte as the drive manufacturer counts it, and as the box advertises.
2,000 GB = 2 TB
The usual sweet spot for price per unit of storage.
4,000 GB = 4 TB
Where desktop drives start costing meaningfully more per unit.

How the gb to tb calculation works

Using the decimal definition, 1 TB = 1,000 GB:

terabytes = gigabytes ÷ 1000

Why your 1 TB drive shows 931 GB. This is the most-asked question about digital storage, and nothing is wrong with the drive.

A manufacturer sells 1 TB as 1,000,000,000,000 bytes — the SI meaning of "tera", and what the box says. Windows then divides by 1,024 three times:

1,000,000,000,000 ÷ 1,024 ÷ 1,024 ÷ 1,024 = 931.32

and displays "931 GB". The correct label for that figure is 931 GiB (gibibytes), but Windows writes GB. Same bytes, two conventions, one confusing number. macOS and Linux report 1,000 GB and agree with the box.

Expected capacities:

Sold as Actual bytes Windows shows
500 GB 500,000,000,000 465 GB
1 TB 1,000,000,000,000 931 GB
2 TB 2,000,000,000,000 1.82 TB
4 TB 4,000,000,000,000 3.64 TB

Formatting takes a further slice for the file system — typically under 1% on NTFS, more on older systems.

A class action against several drive makers over this labelling was settled in 2007; the outcome was a footnote on the box, not a change in the definition.

For anything you are budgeting — backups, media libraries, RAID capacity — plan with the Windows figure, since that is the space you can actually fill.

Frequently asked questions

Why does a 1 TB drive show as 931 GB?

The manufacturer counts a terabyte as a million million bytes, and Windows divides by 1,024 three times, arriving at 931 which it then labels GB. Every byte you paid for is present; the two figures describe the same drive in different units. macOS and Linux report the decimal figure and agree with the box.

How much storage do I actually need?

For documents and photographs, 500 GB is generous. Video is what consumes space: an hour of 4K footage runs to roughly 50 GB. If you edit video or keep a large game library, 2 TB is a sensible floor. If you do neither, a bigger drive mostly buys reassurance rather than capacity you will use.

Is an SSD faster than a hard disk of the same size?

Enormously, and the difference is in access time rather than raw transfer rate. An SSD responds in microseconds where a spinning disk takes several milliseconds, which is why a machine feels quicker even when both quote similar sequential speeds. Hard disks remain much cheaper per terabyte for bulk archival storage.

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Further reading