The Prefixes of the S I

The S I allows the sizes of units to be made bigger or smaller by the use of appropriate prefixes. For example, the electrical unit of a watt is not a big unit even in terms of ordinary household use, so it is generally used in terms of 1000 watts at a time. The prefix for 1000 is kilo so we use kilowatts[kW] as our unit of measurement. For makers of electricity, or bigger users such as industry, it is common to use megawatts[MW] or even gigawatts[GW]. The full range of prefixes with their [symbols or abbreviations] and their multiplying factors which are also given in other forms is
yotta [Y] 1 000 000 000 000 000 000 000 000     = 10^24
zetta [Z] 1 000 000 000 000 000 000 000         = 10^21
exa   [E] 1 000 000 000 000 000 000             = 10^18
peta  [P] 1 000 000 000 000 000                 = 10^15
tera  [T] 1 000 000 000 000                     = 10^12
giga  [G] 1 000 000 000 		   (a thousand millions = a billion)
mega  [M] 1 000 000 			   (a million)
kilo  [k] 1 000 			   (a thousand)
hecto [h] 100                              (a hundred)
deca  [da]10                               (ten)
	  1
deci  [d] 0.1                              (a tenth)
centi [c] 0.01                             (a hundredth)
milli [m] 0.001 			   (a thousandth)
micro [µ] 0.000 001 			   (a millionth)
nano  [n] 0.000 000 001 		   (a thousand millionth)
pico  [p] 0.000 000 000 001			= 10^-12
femto [f] 0.000 000 000 000 001			= 10^-15
atto  [a] 0.000 000 000 000 000 001		= 10^-18
zepto [z] 0.000 000 000 000 000 000 001		= 10^-21
yocto [y] 0.000 000 000 000 000 000 000 001	= 10^-24
[µ] the symbol used for micro is the Greek letter known as 'mu'
Nearly all of the S I prefixes are multiples (kilo to yotta) or sub-multiples (milli to yocto) of 1000. However, these are inconvenient for many purposes and so hecto, deca, deci, and centi are also used.
Factor Prefix Symbol
1012 tera T
109 giga G
106 mega M
103 kilo k
102 hecto h
10 deca da
10-1 deci d
10-2 centi c
10-3 milli m
10-6 micro
10-9 nano n
10-12 pico p