Giga (symbol: G) is a prefix in the SI system of units denoting 10⁹, or 1 000 000 000.

Confirmed in 1960, it comes from the Greek γίγας, meaning giant.

In computing, giga can sometimes mean 1 073 741 824 (2³⁰) for information units, eg gigabit or gigabyte, but can also denote 1 000 000 000 of other quantities, e.g. transfer rates: 1 gigabit/s = 1 000 000 000 bit/s. The binary prefix gibi has been suggested for 2³⁰, to resolve this ambiguity, but had yet to achieve widespread usage.

In speech, gigabyte is often abbreviated to gig, as in "This is a ten-gig hard drive". The initial G in giga- is usually pronounced hard as in geek, not soft as in giant. However, in the 1985 movie Back to the Future, the term giga was pronounced with a soft g sound, as jiga, in the word gigawatts. This was before units like gigabyte were commonplace.

Common usage

• Gigabyte — hard disk capacity, e.g. 120 Gb; DVD capacity, e.g. 5 Gb = 5 × 1 073 741 824 bytes.
• Gigahertz — clock rate of a CPU, e.g. 3 GHz = 3 000 000 000 Hz

See also

• SI prefix
• Binary prefix
• gibibyte
• Gigabit Ethernet

External link

• BIPM website