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## #1 2021-05-15 16:54:49

Jai Ganesh
Registered: 2005-06-28
Posts: 46,437

### The 20 SI Prefixes

The 20 SI Prefixes

Refresher

Multiple  :    Amount  :    Prefix  :  Symbol

:  1 million million-million-millions  :  yotta  :  Y
:  1 thousand million-million-millions  :  zetta  :  Z
:  1 million million-millions  :  exa  :  E
:  1 thousand million-millions  :  peta  :  P
:  1 million millions  :  tera  :  T
:  1 thousand millions  :  giga  :  G
:  1 million  :  mega  :  M
:  1 thousand    :  kilo  :  k
:  1 hundred  :  hecto  :  h
:  ten  :  deca  :  da

Sub-multiple  :  Fraction  :  Prefix  :  Symbol

:  1 tenth  :  deci  :  d
:  1 hundredth  :  centi  :  c
:  1 thousandth  :  milli  :  m
:  1 millionth  :  micro  :  µ
:  1 thousandth of a millionth  :  nano  :  n
:  1 millionth of a millionth  :  pico  :  p
:  1 thousandth of a millionth of a millionth  :  femto  :  f
:  1 millionth of a millionth of a millionth  :  atto  :  a
:  1 thousandth of a millionth of a millionth of a millionth  :  zepto  :  z
:  1 millionth of a millionth of a millionth of a millionth  :  yocto  :  y.

All prefixes should be printed in upright type with no spaces or periods between the prefix and the unit symbol. i.e. kilometre = km, not k m, k.m or km

Prefixes should not be used on its own or combined into multiples compound prefixes. i.e. pg not µµg; 10 µg, not mcg.

The base unit “kg” already contains the prefix “k” for “kilo” (1000). Prefixes should be added to the physical quantity “gram”. i.e. mg not µkg; Mg, not kkg.

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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