GB to TB Converter
Convert gigabytes to terabytes for hard drives, NAS planning and backup sizing. 1 TB = 1000 GB (decimal) or 1024 GiB (binary) — both shown.
Last updated: May 2026
Enter a value to see the conversion instantly.
How to convert gigabytes to terabytes
Large libraries, backups and drive purchases are easier to judge in terabytes, while many file managers and app dashboards still report gigabytes. This page helps bridge that gap. For this example, 1 GB equals 0.001 TB.
The formula is terabytes = gigabytes ÷ 1000. In practice, this is useful when deciding whether a new SSD, NAS volume or backup target is large enough for the total amount of data you expect to store.
Typical use cases
- Comparing media libraries with drive capacity
- Planning backups for photos, games, video or project archives
- Checking how much room is left before a storage upgrade is needed
A common use case is a home NAS or media server. People often think in terabytes for buying storage, but the software may display gigabytes.
Quick reference
| GB | TB |
|---|---|
| 100 | 0.1 |
| 1 | 0.001 |
| 500 | 0.5 |
| 1000 | 1 |
| 2000 | 2 |
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Frequently Asked Questions
Why do backup systems suddenly demand TB numbers?
Professional storage and backup targets are sold in terabytes (NAS, external drives, cloud storage tiers). But when you check total media on your system, it's reported in gigabytes. A photo library of 800 GB needs to fit in "1 TB" NAS—this calculator confirms it has just enough room (with 200 GB free). Without conversion, you risk buying undersized storage and running out mid-backup.
Do TB and Terabytes always mean the same thing?
Not exactly. TB in marketing (like "1TB drive") usually means 1 trillion bytes (decimal). Some systems use TiB (tebibytes, binary = 1.0995 trillion bytes). A 1 TB advertised drive has slightly less usable space after formatting—typically 931-950 GB depending on the file system. This page uses decimal conversion, matching how drives are marketed and sold.
Why is my backup software saying my 2TB drive only holds 1.8TB?
Because formatting (creating a file system) consumes ~8% of raw storage. Overhead for partition tables, file allocation tables, and reserved sectors reduces effective capacity. Additionally, if the drive uses binary convention internally while advertising decimal TB, the mismatch compounds. Always budget 10-15% overhead when planning backups—a 2TB drive in practice holds ~1.7-1.8 TB of actual files.