• 1 Gigabyte (GB) is about a billion-character i.e., 1000 MB or 1 thousand megabytes
• Gigabyte is a common unit for modern hardware for example 4000 MB = 4 GB
• An ordinary computer has 4 GB of RAM 256 GB of storage
• A DVD has a size 4.7GB
• A flash drive has about 32 GB and a hard drive has 750 GB
• 1 kilobyte (KB) is nearly about 1000 bytes. An ordinary Roman text requires about 2 kilobytes to store
• A Terabyte (TB) of computer storage capacity that is nearly about 2 to the 40th power, or 10 to the 12th power. A Terabyte is approximately 1,024 gigabytes (GB)
• The megabyte (MB) is a multiple-unit byte. The word mega represents 1000000 (106) in the International System of Units (SI). Megabyte is also represented by 1000×1024 (1024000) bytes.
• Therefore, 1 Gigabyte represents one billion characters.

Source: Lucent’s Computer