02-06-2023-1246 - metric prefix

A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit. All metric prefixes used today are decadic. Each prefix has a unique symbol that is prepended to any unit symbol. The prefix kilo-, for example, may be added to gram to indicate multiplication by one thousand: one kilogram is equal to one thousand grams. The prefix milli-, likewise, may be added to metre to indicate division by one thousand; one millimetre is equal to one thousandth of a metre.

Decimal multiplicative prefixes have been a feature of all forms of the metric system, with six of these dating back to the system's introduction in the 1790s. Metric prefixes have also been used with some non-metric units. The SI prefixes are metric prefixes that were standardised for use in the International System of Units (SI) by the International Bureau of Weights and Measures (BIPM) in resolutions dating from 1960 to 2022.^[1][2] Since 2009, they have formed part of the ISO/IEC 80000 standard. They are also used in the Unified Code for Units of Measure (UCUM).

 

The BIPM specifies twenty-four prefixes for the International System of Units (SI).

SI prefixes

• v
• t
• e

Prefix		Base 10	Decimal	Adoption [nb 1]
Name	Symbol
quetta	Q	1030	1000000000000000000000000000000	2022[3]
ronna	R	1027	1000000000000000000000000000	2022
yotta	Y	1024	1000000000000000000000000	1991
zetta	Z	1021	1000000000000000000000	1991
exa	E	1018	1000000000000000000	1975
peta	P	1015	1000000000000000	1975
tera	T	1012	1000000000000	1960
giga	G	109	1000000000	1960
mega	M	106	1000000	1873
kilo	k	103	1000	1795
hecto	h	102	100	1795
deca	da	101	10	1795
		100	1	—
deci	d	10−1	0.1	1795
centi	c	10−2	0.01	1795
milli	m	10−3	0.001	1795
micro	μ	10−6	0.000001	1873
nano	n	10−9	0.000000001	1960
pico	p	10−12	0.000000000001	1960
femto	f	10−15	0.000000000000001	1964
atto	a	10−18	0.000000000000000001	1964
zepto	z	10−21	0.000000000000000000001	1991
yocto	y	10−24	0.000000000000000000000001	1991
ronto	r	10−27	0.000000000000000000000000001	2022
quecto	q	10−30	0.000000000000000000000000000001	2022
Notes

Prefixes adopted before 1960 already existed before SI. The introduction of the CGS system was in 1873.

 https://en.wikipedia.org/wiki/Metric_prefix