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SI prefixes

Decimal multiples and submultiples of SI units can be written using the SI prefixes listed in the table below:


Factor Name Symbol Multiplying Factor
1024
yotta
Y
1 000 000 000 000 000 000 000 000
1021
zetta
Z
1 000 000 000 000 000 000 000
1018
exa
E
1 000 000 000 000 000 000
1015
peta
P
1 000 000 000 000 000
1012
tera
T
1 000 000 000 000
109
giga
G
1 000 000 000
106
mega
M
1 000 000
103
kilo
k
1 000
102
hecto
h
100
101
deca
da
10
10–1
deci
d
0.1
10–2
centi
c
0.01
10–3
milli
m
0.001
10–6
micro
µ
0.000 001
10–9
nano
n
0.000 000 001
10–12
pico
p
0.000 000 000 001
10–15
femto
f
0.000 000 000 000 001
10–18
atto
a
0.000 000 000 000 000 001
10–21
zepto
z
0.000 000 000 000 000 000 001
10–24
yocto
y
0.000 000 000 000 000 000 000 001


For full details please refer to Chapter 3 of the SI Brochure.