Metric System
Prefix Symbol Mathematical power Number Name
exa E 10 18 1 000 000 000 000 000 000 one quintillion
peta P 10 15 1 000 000 000 000 000 one quadrillion
tera T 10 12 1 000 000 000 000 one trillion
giga G (or B) 10 9 1 000 000 000   one billion (or milliard)
mega M 10 6 1 000 000 one million
kilo k 10 3 1 000 one thousand
hecto h 10 2 100 one hundred
deca da 10 1 10 ten
basic unit   10 0 1   one
deci d 10-1 0.1 one tenth
centi c 10-2 0.01 one hundredth
milli m 10-3 0.001 one thousandth
micro μ 10-6 0.000 001 one millionth
nano n 10-9   0.000 000 001 one billionth (or milliardth)
pico p 10-12 0.000 000 000 001 one trillionth
femto f 10-15 0.000 000 000 000 001 one quadrillionth
atto a 10-18 0.000 000 000 000 000 001 one quintillionth