How many GB are in 1 TB?

In the SI decimal standard (used by drive makers, macOS, and most cloud providers), 1 terabyte (TB) equals exactly 1,000 gigabytes (GB). So 1 GB = 0.001 TB.

How many GiB are in 1 TiB?

In the binary IEC standard, 1 tebibyte (TiB) equals exactly 1,024 gibibytes (GiB). Windows uses this binary calculation internally but still displays the label "TB", which is why advertised capacity looks smaller in Windows Explorer.

Why does my 1 TB drive show less in Windows?

Drive makers define 1 TB as 10^12 bytes (SI). Windows measures capacity in binary units but labels them GB and TB. Because 10^12 ÷ 2^30 ≈ 931.32, a 1 TB drive appears as about 931 GB (or ~0.909 TB if measured against 2^40 bytes) in Windows.

What is the formula to convert GB to TB?

SI decimal: TB = GB ÷ 1,000. Binary IEC: TiB = GiB ÷ 1,024. For example, 2,500 GB ÷ 1,000 = 2.5 TB (SI), and 2,500 GiB ÷ 1,024 ≈ 2.441 TiB (binary).

Which standard does macOS use?

Since macOS 10.6 (Snow Leopard), Apple uses SI decimal units. Finder shows 1 TB as exactly 1,000,000,000,000 bytes, matching the capacity printed on the drive box.

Is GB the same as GiB?

No. GB (gigabyte) is the SI unit: 1 GB = 10^9 bytes = 1,000,000,000 bytes. GiB (gibibyte) is the IEC binary unit: 1 GiB = 2^30 bytes = 1,073,741,824 bytes. They differ by about 7.4%. Many older tools and operating systems used "GB" when they meant "GiB".

Gigabytes to Terabytes Converter

Enter any gigabyte value and instantly get the terabyte equivalent in both SI decimal (1 TB = 1,000 GB) and binary IEC (1 TiB = 1,024 GiB) standards.

GB to TB Converter

Gigabytes (GB / GiB)

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Summary

This converter translates gigabytes (GB) to terabytes (TB) using both the SI decimal standard (1 TB = 1,000 GB) and the binary IEC standard (1 TiB = 1,024 GiB). All calculation happens in your browser — no server call needed. Along with the converted result you get the precise byte count, the step-by-step formula, and a copy button for each value.

How it works

Type any gigabyte value into the input field.
The SI result divides your value by 1,000 to get terabytes.
The binary result divides your value by 1,024 to get tebibytes (TiB).
The byte count panel shows the exact number of bytes represented.
Click "Copy" next to any result to copy it to your clipboard.
Click "Clear" to reset the converter.

Use cases

Check how many terabytes a 500 GB backup archive occupies on a NAS.
Understand why a "1 TB" Windows drive shows roughly 931 GB (binary vs. decimal difference).
Convert cloud storage quotas listed in GB into the TB figure that appears on your bill.
Calculate how much of a terabyte-scale database volume a gigabyte-sized dataset uses.
Compare manufacturer-advertised TB capacity against OS-reported GiB figures.
Estimate data transfer costs when a provider charges per TB but files are sized in GB.
Verify that a VM disk image measured in GB fits within a provisioned TB volume.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu