# Gigabytes to terabytes converter

> Convert gigabytes to terabytes (GB to TB) with the exact factor, a conversion chart and worked steps.

Interactive version: https://www.calcopenly.com/conversion/gb-to-tb
Subject: Unit converters

Gigabytes may describe a data plan, a collection of files or a drive partition. Converting that allowance helps compare it with a differently labelled quota. Keep decimal GB separate from GiB and distinguish storage capacity from a transfer rate.

One gigabyte is exactly 0.001 terabytes, so 500 GB is 0.5 TB. To convert GB to TB, multiply by 0.001; to convert back, multiply by 1,000.

Because both units are defined exactly, the factor above is exact and the results here carry no conversion error.

## Inputs

- **Gigabytes (GB)**

## Results

- Terabytes (TB) — main result
- Conversion
- 1 TB in gigabytes (GB)

## Formula

$$
\text{terabytes} = \text{gigabytes} \times 0.001
$$

## Worked examples

### 500 GB to TB

- Gigabytes (GB): 500 GB
- **Terabytes: 0.5 TB**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 2000 GB to TB

- Gigabytes (GB): 2000 GB
- **Terabytes: 2 TB**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 128 GB to TB

- Gigabytes (GB): 128 GB
- **Terabytes: 0.128 TB**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### What fraction of a terabyte is 500 GB?

500 decimal GB is 0.5 TB. Divide the gigabyte amount by 1,000 when comparing file totals with a terabyte quota. Keep the same decimal convention on both sides of the comparison.

### How many terabytes are in a gigabyte?

One gigabyte is exactly 0.001 terabytes.

### How do you convert GB to TB?

Multiply the number of gigabytes by 0.001. For example, 500 GB × 0.001 = 0.5 TB. To go the other way, divide by 0.001.

### Why does my computer show less space than the drive's label?

Drive makers count 1 GB as 1,000,000,000 bytes, while Windows and some other systems count in binary units of 1,073,741,824 bytes but still label them GB. A 1 TB drive therefore appears as about 931 GB (really 931 GiB).

### How accurate is the gigabytes to terabytes converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “500 GB to TB” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.

## Sources

- [NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C: General tables of units of measurement](https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-44)
- [BIPM, The International System of Units (SI Brochure), 9th edition](https://www.bipm.org/en/publications/si-brochure)