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SI Number Prefixes Chart


The following table shows the number prefixes as defined by the International System of Units (SI Units) used in science, engineering, finance etc.

Prefix Symbol 10n Decimal Short scale Long scale
yotta Y 1024 1 000 000 000 000 000 000 000 000 Septillion Quadrillion
zetta Z 1021 1 000 000 000 000 000 000 000 Sextillion Trilliard
exa E 1018 1 000 000 000 000 000 000 Quintillion Trillion
peta P 1015 1 000 000 000 000 000 Quadrillion Billiard
tera T 1012 1 000 000 000 000 Trillion Billion
giga G 109 1 000 000 000 Billion Milliard
mega M 106 1 000 000 Million
kilo k 103 1 000 Thousand
hecto h 102 100 Hundred
deca da 101 10 Ten
  100 1 One
deci d 10−1 0.1 Tenth
centi c 10−2 0.01 Hundredth

milli m 10−3 0.001 Thousandth
micro μ 10−6 0.000 001 Millionth
nano n 10−9 0.000 000 001 Billionth Milliardth
pico p 10−12 0.000 000 000 001 Trillionth Billionth
femto f 10−15 0.000 000 000 000 001 Quadrillionth Billiardth
atto a 10−18 0.000 000 000 000 000 001 Quintillionth Trillionth
zepto z 10−21 0.000 000 000 000 000 000 001 Sextillionth Trilliardth
yocto y 10−24 0.000 000 000 000 000 000 000 001 Septillionth Quadrillionth