Mega-

Template:Short description Mega is a unit prefix in metric systems of units denoting a factor of one million (10⁶ or ). It has the unit symbol M. It was confirmed for use in the International System of Units (SI) in 1960. Mega comes from Template:Langx.

Common examples of usage

• Megapixel: 1 million pixels in a digital camera
• One megatonne of TNT equivalent amounts to approx. 4 petajoules and is the approximate energy released on igniting one million tonnes of TNT. The unit is often used in measuring the explosive power of nuclear weapons.
• Megahertz: frequency of electromagnetic radiation for radio and television broadcasting, GSM, etc. 1 MHz = 1,000,000 Hz.
• Megabyte: unit of information equal to one million bytes (SI standard).
• Megawatt: equal to one million watts of power. It is commonly used to measure the output of power plants, as well as the power consumption of electric locomotives, data centers, and other entities that heavily consume electricity.
• Megadeath: (or megacorpse) is one million human deaths, usually used in reference to projected number of deaths from a nuclear explosion. The term was used by scientists and thinkers who strategized likely outcomes of all-out nuclear warfare.

Exponentiation

When units occur in exponentiation, such as in square and cubic forms, any multiples-prefix is considered part of the unit, and thus included in the exponentiation.

• 1 Mm² means one square megametre or the size of a square of by or , and not (10⁶ m²).
• 1 Mm³ means one cubic megametre or the size of a cube of by by or 10¹⁸ m³, and not (10⁶ m³)

Computing

In some fields of computing, mega may sometimes denote (2²⁰) information units, for example, a megabyte, a megaword, but denotes (10⁶) units of other quantities, for example, transfer rates: = . In the case of 3½-inch floppy disks, sizes were given in megabytes of 1000 kB or bytes. The prefix mebi- has been suggested as a prefix for 2²⁰ to avoid ambiguity.

See also

• Binary prefix
• Mebibyte
• Order of magnitude
• RKM code

External links

• BIPM website

SI prefixes

Prefix		Base 10	Decimal	Adoption
Name	Symbol
quetta	Q	1030		2022
ronna	R	1027
yotta	Y	1024		1991
zetta	Z	1021
exa	E	1018		1975
peta	P	1015
tera	T	1012		1960
giga	G	109
mega	M	106		1873
kilo	k	103		1795
hecto	h	102	100
deca	da	101	10
—	—	100	1	—
deci	d	10−1	0.1	1795
centi	c	10−2	0.01
milli	m	10−3	0.001
micro	μ	10−6		1873
nano	n	10−9		1960
pico	p	10−12
femto	f	10−15		1964
atto	a	10−18
zepto	z	10−21		1991
yocto	y	10−24
ronto	r	10−27		2022
quecto	q	10−30
Notes