The most commonly used metric prefixes

Prefix	Symbol	Factor	Numerically	Name
giga	G	109	1 000 000 000	billion**
mega	M	106	1 000 000	million
kilo	k	103	1 000	thousand
centi	c	10-2	0.01	hundredth
milli	m	10-3	0.001	thousandth
micro	μ	10-6	0.000 001	millionth
nano	n	10-9	0.000 000 001	billionth**

**	The terms billion, trillion, etc., can be ambiguous. The terms are used here in the American English sense, but British English traditionally defined billion as a million million, rather than a thousand million. However, recent British usage tends to match the American meanings.