Symbol

Measure

Decimal equivalent

Exponential

expression

y – yocto

0.000 000 000 000 000 000 000 001

E^-24

z – zepto

0.000 000 000 000 000 000 001

E^-21

a – atto

one-quintillionth

0.000 000 000 000 000 001

E^-18

f – femto

one-quadrillionth

0.000 000 000 000 001

E^-15

p – pico

one-trillionth

0.000 000 000 001

E^-12

n – nano

one-billionth

0.000 000 001

E^-9

μ – micro

one-millionth

0.000 001

E^-6

m – milli

one-thousandth

0.001

E^-3

c – centi

one-hundredth

0.01

E^-2

d – deci

one-tenth

0.1

E^-1

Uni

one

1

E⁰

d – deka

ten

10

E¹

h – hecto

one hundred

100

E²

k – kilo

one thousand

1000

E³

M – mega

one million

1000000

E⁶

G – giga

one billion

1000000000

E⁹

T – tera

one trillion

1000000000000

E¹²

P – peta

1 000 000 000 000 000

E¹⁵

E – exa

1 000 000 000 000 000 000

E¹⁸

Z – zetta

1 000 000 000 000 000 000 000

^E21

Y – yotta

1 000 000 000 000 000 000 000 000

^E24