# Gigabytes to Terabytes (GB to TB)

> Convert gigabytes to terabytes: 1 GB = 0.001 TB. Exact conversion factor, formula, 18-row table and worked examples, with JSON API and MCP access.

- Page id: `gb-to-tb` · Quantity: Data storage (`data-storage`, base unit B) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/gb-to-tb · This document: https://tttkmbb.com/conversion/gb-to-tb.md · JSON: https://tttkmbb.com/conversion/gb-to-tb.json (add `?value=` for a result)

## Formula

- `1 GB = 0.001 TB`
- `terabytes = gigabytes × 0.001`
- Reverse: `gigabytes = terabytes × 1000`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 1.5 GB = 0.0015 TB
- 700 GB = 0.7 TB
- 2048 GB = 2.048 TB

## Conversion table

| Gigabytes (GB) | Terabytes (TB) |
| --- | --- |
| 1 | 0.001 |
| 2 | 0.002 |
| 4 | 0.004 |
| 8 | 0.008 |
| 16 | 0.016 |
| 32 | 0.032 |
| 64 | 0.064 |
| 100 | 0.1 |
| 128 | 0.128 |
| 256 | 0.256 |
| 500 | 0.5 |
| 512 | 0.512 |
| 1000 | 1 |
| 1024 | 1.024 |
| 2048 | 2.048 |
| 4096 | 4.096 |
| 8192 | 8.192 |
| 10000 | 10 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=1.5&from_unit=GB&to_unit=TB` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":1.5,"from_unit":"GB","to_unit":"TB"}`
- All data storage units: https://tttkmbb.com/api/v1/units?quantity=data-storage · full converter: [Data Storage Converter](https://tttkmbb.com/conversion/data-storage.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many terabytes are in one gigabyte?**

1 GB = 0.001 TB. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

**What is the formula to convert gigabytes to terabytes?**

Multiply the value in gigabytes by 0.001: terabytes = gigabytes × 0.001. For example, 1.5 GB = 0.0015 TB.

**How do I convert terabytes back to gigabytes?**

Multiply by the inverse factor 1000 (gigabytes = terabytes × 1000), or use the terabytes-to-gigabytes page.

## Related conversions

- [Terabytes to gigabytes](https://tttkmbb.com/conversion/tb-to-gb.md) (reverse)
- [Megabytes to Gigabytes](https://tttkmbb.com/conversion/mb-to-gb.md)
- [Gigabytes to Megabytes](https://tttkmbb.com/conversion/gb-to-mb.md)
- [Kilobytes to Megabytes](https://tttkmbb.com/conversion/kb-to-mb.md)
- [Megabytes to Kilobytes](https://tttkmbb.com/conversion/mb-to-kb.md)
- [Mebibytes to Megabytes](https://tttkmbb.com/conversion/mib-to-mb.md)
- [Megabytes to Mebibytes](https://tttkmbb.com/conversion/mb-to-mib.md)
- [Gibibytes to Gigabytes](https://tttkmbb.com/conversion/gib-to-gb.md)
- [Gigabytes to Gibibytes](https://tttkmbb.com/conversion/gb-to-gib.md)

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)