What is gigabyte (decimal)?

A gigabyte in the decimal system is a data unit equal to 1,000 megabytes. It is widely used to express storage device capacity, RAM size, file sizes, and data transfer quotas in consumer electronics and networking.

Real-world uses

Gigabytes are the standard unit for smartphone storage (64–512 GB), laptop hard drives (256 GB–2 TB), monthly mobile data plans (5–100 GB), and video files. A 4K video file runs about 50–100 GB per hour uncompressed, or 4–10 GB per hour when compressed (H.264/H.265).

History

The gigabyte became the dominant consumer storage unit in the late 1990s and 2000s as hard drive capacities surpassed the megabyte range. Flash storage in phones and USB drives in the gigabyte range popularised the term with mainstream consumers in the 2000s–2010s.

Common mistakes

The decimal vs. binary discrepancy is most visible with gigabytes: 1 GB = 1,000,000,000 bytes (SI/marketing), while the OS may display the same drive capacity as ~0.93 GiB. A "256 GB" phone shows roughly 238 GiB available. The binary equivalent is the gibibyte (GiB).

What is terabyte (decimal)?

A terabyte in the decimal system is a data unit equal to 1,000 gigabytes. It is the standard unit used by hard drive and SSD manufacturers, cloud storage providers, and for internet traffic measurement.

Real-world uses

Terabytes are the standard unit for consumer hard drives (1–8 TB), NAS storage, cloud backup plans, and data centre capacity. A 2-hour 4K Blu-ray film uncompressed is about 100 GB; streaming services store thousands of hours of content in terabyte scale. Enterprise databases and analytics platforms operate in the terabyte to petabyte range.

History

The first consumer 1 TB hard drive (Hitachi Deskstar 7K1000) was released in 2007. Since then, drive capacities have grown to 20+ TB. The term "terabyte" saw widespread consumer use from the late 2000s onwards as personal backup and media storage needs grew into this range.

Common mistakes

As with gigabytes, a "1 TB" drive from a manufacturer contains 1,000,000,000,000 bytes (decimal), but Windows reports it as approximately 931 GiB (binary). Users often think storage is missing. 1 TB ≈ 0.909 TiB.

When is this conversion used?

Operating systems and storage manufacturers use different base systems (binary vs decimal), which is why a '1 TB' drive shows less than 1 TB in your file manager. Understanding this conversion prevents confusion about available storage.

Worked examples

1 gigabyte (decimal) = 0.001 terabyte (decimal)

1 terabyte (decimal) = 1.000000e+12 byte

How to convert gigabyte (decimal) to terabyte (decimal)

To convert gigabyte (decimal) to terabyte (decimal), multiply the value by 0.001.

To convert terabyte (decimal) back to gigabyte (decimal), multiply by 1,000.

Measurement standards

The International Electrotechnical Commission (IEC 80000-13) defines binary prefixes: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes. The SI decimal prefixes (kB = 1,000 bytes, MB = 1,000,000 bytes) apply to data units as they do to all SI quantities.

Did you know?

By 2025, the global datasphere is estimated to reach 181 zettabytes — roughly 181 trillion gigabytes. If stored on standard Blu-ray discs, the stack would reach from Earth to Mars and back over 20 times.

Quick reference: gigabyte (decimal) to terabyte (decimal)

gigabyte (decimal)terabyte (decimal)
0.10.0001
0.50.0005
10.001
20.002
50.005
100.01
250.025
500.05
1000.1
2500.25
5000.5
1,0001

Common values

gigabyte (decimal)terabyte (decimal)
A text email0.000005 gigabyte (decimal)5.000000e-09 terabyte (decimal)
An MP3 song (4 min)0.004 gigabyte (decimal)0.000004 terabyte (decimal)
A smartphone photo0.005 gigabyte (decimal)0.000005 terabyte (decimal)
An HD movie5 gigabyte (decimal)0.005 terabyte (decimal)
A full hard drive1,000 gigabyte (decimal)1 terabyte (decimal)