Prefixes Used in the SI System

Prefix

Symbol

Meaning

Exponential
Notation

exa

E

1,000,000,000,000,000,000

1018

peta

P

1,000,000,000,000,000

1015

tera

T

1,000,000,000,000

1012

giga

G

1,000,000,000

109

mega

M

1,000,000

106

kilo

k

1,000

103

hecto

h

100

102

deka

da

10

101

   

1

100

deci

d

0.1

10-1

centi

c

0.01

10-2

milli

m

0.001

10-3

micro

0.000001

10-6

nano

n

0.000000001

10-9

pico

p

0.000000000001

10-12

femto

f

0.000000000000001

10-15

atto

a

0.000000000000000001

10-18