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GB to TB Converter

Gigabytes to terabytes, both directions — including the number nobody else shows you: what Windows will actually display for that drive.

Decimals:
3
My numbers come from:
1 TB = 1,000 GB — what the box and the spec sheet mean
GB

SSD sizes, phone storage, cloud plans, game installs.

TB

External drives, NAS capacity, backup targets.

Try a drive:

How Many GB in a TB?

1 TB = 1,000 GB — the decimal (SI) definition used on every drive box, phone spec, and cloud plan. The binary system runs parallel: 1 TiB = 1,024 GiB, and at terabyte scale the two drift 9.95% apart — the biggest gap yet on the unit ladder, and the entire reason your "1 TB" drive shows ~931 GB in Windows.

TB = GB ÷ 1,000 (decimal)  ·  TiB = GiB ÷ 1,024 (binary)  ·  per NIST and IEC 80000-13

The decimal-binary gap grows with every step up the ladder — 2.4% at kilobytes, 4.9% at megabytes, 7.4% at gigabytes, and now nearly 10% at terabytes. That's why this conversion generates more "where did my space go?" confusion than any other pair: the bigger the drive you buy, the bigger the apparent shortfall. It's accounting, not missing hardware — and the calculator above shows you the Windows-displayed figure directly so there are no surprises at checkout. The full decimal-vs-binary story, with the OS behavior table and drive label decoder, is in our GB vs GiB guide; the raw unit conversion has its own GB to GiB converter. Factors documented in our methodology.

What Your Drive Will Really Show

Every common drive size: the label, what Windows displays, and the "missing" space that was never missing.

Advertised drive capacities versus what operating systems display
On the boxExact bytesWindows displaysApparent "loss"
256 GB256,000,000,000≈ 238 GB~18 GB
500 GB500,000,000,000≈ 465 GB~35 GB
1 TB1,000,000,000,000≈ 931 GB~69 GB
2 TB2,000,000,000,000≈ 1.81 TB~186 GB
4 TB4,000,000,000,000≈ 3.63 TB~372 GB
8 TB8,000,000,000,000≈ 7.27 TB~745 GB

"Windows displays" = bytes ÷ 1,024⁴ (or ÷1,024³ for GB-scale), labeled TB/GB but really TiB/GiB. Formatting and file-system overhead subtract another 1–2% of usable space on top. The drive always contains every advertised byte.

Common GB Values, Converted

Each with its decimal conversion and the on-screen figure that surprises people.

500 GB = 0.5 TB

  • OS will display: 465 GB
  • Standard laptop SSD class

1,000 GB = 1 TB

  • OS will display: 931 GB
  • The classic 1 TB drive

1,024 GB = 1.024 TB

  • OS will display: 953 GB
  • Exactly 1 TiB if read as binary

2,000 GB = 2 TB

  • OS will display: 1.81 TB
  • Mainstream external drive size

4,000 GB = 4 TB

  • OS will display: 3.63 TB
  • NAS and backup drive class

8,000 GB = 8 TB

  • OS will display: 7.27 TB
  • High-capacity desktop HDD

GB to TB Conversion Table

Formula: TB = GB ÷ 1,000

GB to TB

GigabytesTB (decimal)TiB (binary)
100 GB0.10.091
250 GB0.250.227
500 GB0.50.455
1,000 GB10.909
1,024 GB1.0240.931
2,000 GB21.819
5,000 GB54.547
10,000 GB109.095
100,000 GB10090.95

TB to GB

TerabytesGB (decimal)Typical context
0.5 TB500Laptop SSD
1 TB1,000Standard external drive
2 TB2,000Cloud plan / portable HDD
4 TB4,000Backup / NAS drive
8 TB8,000High-capacity desktop HDD
12 TB12,000Enterprise / surveillance
20 TB20,000Current HDD flagship class
100 TB100,000Small server array

What Actually Fits in a Terabyte?

A terabyte sounds abstract until you fill one. Using typical file sizes (photo ≈ 4 MB, MP3 ≈ 5 MB, compressed HD movie ≈ 4 GB, AAA game ≈ 75 GB):

📷
~250,000

smartphone photos

🎵
~200,000

MP3 songs

🎬
~250

HD movies

🎮
~13

AAA game installs

The game figure is the one that surprises: at 75–150 GB per modern title, a "huge" 1 TB drive holds a shockingly small library — which is why gamers moved to 2 TB as the practical floor. For backup planning, the sturdy rule is 3-2-1: three copies of your data, on two different media, one off-site — meaning your backup drive should be at least as large as everything you're protecting, plus room to grow. Filling a 2 TB drive over the network takes real time too: about 44 hours at 100 Mbps — the download time calculator handles any size-speed pair.

Frequently Asked Questions

Quick answers about GB and TB

How many GB are in 1 TB?
In decimal (SI) units — how every drive, phone, and cloud plan is labeled — 1 TB = 1,000 GB exactly. In binary units, 1 TiB = 1,024 GiB. The gap between the two systems is 9.95% at terabyte scale, which is why a "1 TB" drive appears as roughly 931 GB in Windows.
Is 1 TB equal to 1,024 GB?
Officially no — 1 TB = 1,000 GB by the SI definition all manufacturers use. The 1,024 factor belongs to the binary tebibyte (1 TiB = 1,024 GiB). If you see "1,024 GB" treated as 1 TB, that source is using binary counting with decimal labels — common, but imprecise.
Why does my 2 TB drive show only 1.81 TB?
The drive contains exactly 2,000,000,000,000 bytes as advertised. Windows divides that by 1,024⁴ and displays 1.81 — which is the size in TiB (tebibytes), mislabeled as "TB". Nothing is missing or defective; the manufacturer and the operating system are simply using different counting systems, 9.95% apart at this scale.
How many photos or movies fit on 1 TB?
Roughly 250,000 smartphone photos at 4 MB each, or about 250 compressed HD movies at 4 GB, or around 13 modern AAA game installs at 75 GB. In practice, plan for about 5–10% less usable space after formatting and system overhead.
What is 4 TB in GB?
4 TB = 4,000 GB in decimal units. In Windows, a 4 TB drive displays as approximately 3.63 TB (really 3,725 GiB) because of binary counting. That ~275 GB visual difference is the standard decimal-binary gap, not lost capacity.
Is 1 TB enough storage?
For most people, comfortably: a typical household photo library, music collection, and documents fit in well under 500 GB. The exceptions are 4K video work (1 TB fills in ~35 hours of footage), large game libraries (13–20 modern titles), and complete PC backups — those workloads justify 2 TB or more.

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