SI Metric Prefixes
Purpose Name Symbol Factor Common name Purpose Name Symbol Factor Common name
larger quantities
or whole units
quetta Q 1030 nonillion smaller quantities
or sub units
deci
decimeter
d 10-1 tenth
ronna R 1027 octillion centi
centigram
c 10-2 hundredth
yotta Y 1024 septillion milli
milliliter
m 10-3 thousandth
zetta Z 1021 sextillion micro
microgram
μ 10-6 millionth
exa E 1018 quintillion nano
nanometer
n 10-9 billionth
peta P 1015 quadrillion pico
picogram
p 10-12 trillionth
tera
terahertz
T 1012 trillion femto
femtosecond
f 10-15 quadrillionth
giga
gigawatt
G 109 billion atto a 10-18 quintillionth
mega M 106 million zepto
zeptosecond
z 10-21 sextillionth
kilo
kiloliter
k 103 thousand yocto
yoctosecond
y 10-24 septillionth
hecto
hectare
h 102 hundred ronto r 10-27 octillionth
deka
dekameter
da 101 ten quecto q 10-30 nonillionth
      100 one        

Source: Metric (SI) Prefixes