Gigabytes (GB)

The gigabyte (GB) is 1,000,000,000 bytes under the SI (decimal) definition used by storage manufacturers, network equipment and macOS.

Convert gigabytes to any data unit

1 gigabyte = 1,000 megabytes

Quick facts

Unit
Gigabyte (plural: gigabytes)
Symbol
GB
Measures
Information / Data
System
Decimal (SI)
Equals
1,000,000,000 bytes
Definition
1,000,000,000 bytes (10^9), the SI definition.

1 gigabyte in other units

Megabytes1,000 MB
Bytes1,000,000,000 B
Terabytes0.001 TB
Bits8,000,000,000 bit
Kilobytes1,000,000 kB
Gigabits8 Gbit
Megabits8,000 Mbit
Terabits0.008 Tbit

What is a gigabyte?

The gigabyte (GB) is 1,000,000,000 bytes under the SI (decimal) definition used by storage manufacturers, network equipment and macOS. Windows still reports sizes with 1024-based units but labels them GB, which is why a new drive shows less space than advertised. The binary counterpart is the gibibyte (GiB).

Where the gigabyte sits among data units

The gigabyte is number 33 of 64 on our scale of data units, ordered from smallest to largest.

Mebibyte1 GB = 953.674 MiB Megabyte (1024² bytes)1 GB = 953.674 MB Gigabit1 GB = 8 Gbit Gibibit1 GB = 7.45058 Gibit Gigabytethis unit Gibibyte1 GiB = 1.07374 GB Gigabyte (1024³ bytes)1 GB = 1.07374 GB Terabit1 Tbit = 125 GB Terabyte1 TB = 1,000 GB

Gigabytes in real life

  • A DVD holds 4.7 GB; an hour of HD video streaming uses about 3 GB.

One gigabyte is about 1.4 CDs, or about 1.3 human genomes, or about 21% of a DVD, or about 20% of an HD movie.

Top gigabyte conversions

Common amounts of gigabytes

Convert gigabytes to all 63 other units

Bits & bytes

Decimal (SI)

Binary (IEC)

Legacy binary (JEDEC)

Information theory

Media & everyday comparisons

Convert to gigabytes

Frequently asked questions

What is a gigabyte?

The gigabyte (GB) is 1,000,000,000 bytes under the SI (decimal) definition used by storage manufacturers, network equipment and macOS.

How is the gigabyte defined?

1,000,000,000 bytes (10^9), the SI definition.

How many megabytes are in a gigabyte?

One gigabyte equals 1,000 megabytes.

How many bytes are in a gigabyte?

One gigabyte equals 1,000,000,000 bytes.

How many terabytes are in a gigabyte?

One gigabyte equals 0.001 terabytes.