GB to TB – Gigabytes to Terabytes Converter

Convert between gigabytes (GB) and terabytes (TB) in both decimal (1 TB = 1000 GB) and binary (1 TiB = 1024 GiB) systems. Designed for IT professionals, sysadmins and power users sizing disks, RAID arrays, cloud storage and backup plans.

The engine uses precise byte-level conversions and shows decimal GB/TB alongside binary GiB/TiB, so you immediately see what operating systems and vendors will display.

Gigabytes ⇄ Terabytes converter

Decimal & Binary
Conversion direction
Unit system

Use this when the data sheet or cloud plan quotes capacity in GB.

Results

Decimal GB:
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Decimal TB:
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Binary GiB:
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Binary TiB:
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Bytes:
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Enter a value and click “Convert” to see decimal (GB/TB) and binary (GiB/TiB) equivalents side by side.

GB to TB – quick reference table

Common capacities used in SSDs, HDDs and cloud storage, shown in both decimal and binary forms.

Nominal GB Decimal TB Approx. GiB (binary) Approx. TiB (binary)

Decimal: GB and TB use powers of 10 (1 TB = 10¹² bytes). Binary: GiB and TiB use powers of 2 (1 TiB = 2⁴⁰ bytes). OS values may be labelled “GB” while actually meaning GiB.

GB vs TB vs GiB vs TiB: what are you really converting?

In data storage, the word gigabyte can mean two slightly different things:

  • Decimal gigabyte (GB) – defined by the SI system: 1 GB = 109 bytes (1,000,000,000 bytes).
  • Binary gibibyte (GiB) – defined by IEC: 1 GiB = 230 bytes (1,073,741,824 bytes).

Similarly for terabytes:

  • Decimal terabyte (TB) – 1 TB = 1012 bytes (1,000,000,000,000 bytes).
  • Binary tebibyte (TiB) – 1 TiB = 240 bytes (1,099,511,627,776 bytes).

Key relationships

Decimal: 1 TB = 1000 GB, 1 GB = 1000 MB.

Binary: 1 TiB = 1024 GiB, 1 GiB = 1024 MiB.

Mixed: 1 TB ≈ 0.9095 TiB and 1 TiB ≈ 1.0995 TB.

Formulas used by the GB ⇄ TB calculator

1. Decimal GB and TB (drive vendors, cloud providers)

For decimal units, storage is expressed with powers of 10:

Decimal formulas

TB = GB ÷ 1000

GB = TB × 1000

Example: 500 GB → 500 ÷ 1000 = 0.5 TB.

2. Binary GiB and TiB (operating systems, file systems)

For binary units, storage is expressed with powers of 2:

Binary formulas

TiB = GiB ÷ 1024

GiB = TiB × 1024

Example: 1024 GiB → 1 TiB.

3. Bridging decimal and binary via bytes

To accurately translate between GB/TB and GiB/TiB, you must go through bytes:

Through-bytes conversion

Decimal: bytes = GB × 10⁹, bytes = TB × 10¹²

Binary: GiB = bytes ÷ 2³⁰, TiB = bytes ÷ 2⁴⁰

The calculator performs these steps internally to show all four units consistently.

Typical scenarios and examples

Example 1 – 1 TB HDD and the “931 GB” effect

  1. Vendor rating: 1 TB = 1,000,000,000,000 bytes.
  2. Operating system reports GiB: GiB = bytes ÷ 2³⁰ ≈ 931.32 GiB.
  3. Many OSs label GiB as “GB”, so you see “931 GB” even though the drive is correctly 1 TB by vendor specs.

Example 2 – 750 GB plan to TB and TiB

  1. TB (decimal): 750 ÷ 1000 = 0.75 TB.
  2. Bytes: 750 × 10⁹ = 750,000,000,000 bytes.
  3. GiB: 750,000,000,000 ÷ 2³⁰ ≈ 698.49 GiB.
  4. TiB: 750,000,000,000 ÷ 2⁴⁰ ≈ 0.6817 TiB.

Which convention should you use in practice?

The right convention depends on who will read your numbers:

  • Cloud pricing & vendor specs – almost always decimal GB/TB. Use TB = GB ÷ 1000.
  • Linux, Windows, macOS utilities – often binary GiB/TiB internally; labels may vary between “GB” and “GiB”.
  • Technical documentation – best practice is to use GB/TB for decimal and GiB/TiB for binary and define them once.
  • User-facing UIs – choose one convention and be consistent; provide a short help text for advanced users.

This GB to TB converter helps you quickly move between conventions, so you can reconcile what your vendor sells, what your OS shows and what your capacity planning spreadsheet expects.

Frequently asked questions about GB and TB

Is 1024 GB always equal to 1 TB? ▾
Not in the strict SI sense. In decimal, 1 TB = 1000 GB, so 1024 GB = 1.024 TB. In binary, 1024 GiB = 1 TiB. Many tools loosely call both “1 TB”, which is why showing both decimal and binary values, as this calculator does, is important for clarity.
Why do backup tools show slightly less capacity than advertised? ▾
First, binary units reduce the numeric value from TB to TiB or from GB to GiB. Second, part of the capacity is used for file system metadata, snapshots and over-provisioning. The GB to TB converter isolates the unit effect; the remaining difference comes from overhead and reserved space.
How many TB do I need for a 10 TB nominal RAID-5 array? ▾
Vendors rate each disk in decimal TB; RAID-5 then reserves one disk for parity. For example, 4 × 4 TB disks (nominal 16 TB raw) give about 12 TB usable in decimal terms, but utilities will show fewer TiB. Use this converter with your planned raw GB to understand both views during capacity planning.
Can I simply multiply TB by 1024 to get GB? ▾
Only if you are strictly working in binary units (TiB and GiB). For decimal TB and GB the factor is 1000, not 1024. Mixing the two rules is a common source of errors in sizing spreadsheets and architectural documents.
Is this GB to TB converter suitable for documentation and client reports? ▾
Yes. The tool uses precise byte-based conversions and clearly separates decimal and binary values, which is appropriate for professional IT documentation, client reports and capacity planning. Always indicate in your report which convention you are using and reference the formulas you applied.