Search
prefixsymbol valuevalue 'puter jargon usageorigin / plausible alternative
deca- da
101
101
[3], used to be "deka"
(1790-1866)
Gk. ten "deka"
hecto- h
102
102
[3] Gk. hundred "hekaton"
kilo- k
10001
103
note lower case "k" Gk. thousand "chylioi"
myria- ma, my
104
104
[3], [4] Gk. ten thousand "myrias"
hectokilo- hk
105
105
[4]  
mega- M
10002
106
  Gk. large, great "megas"
giga-G
10003
109
  Gk. giant "gigas"
tera- T
10004
1012
  Gk. monster "teras" / Gk. four "tetra"
peta-P
10005
1015
  Gk. five "penta" / Gk. spread "petalos"
exa-E
10006
1018
  Gk. six hexa" / Gk. outside "exo"
zetta-Z
10007
1021
  L. ultimate letter z "zeta"
yotta- Y
10008
1024
  L. penultimate letter y "iota"
harpi-Hr
10009
1027
[1] Marx Bros. Harpo
grouchi-Gc
100010
1030
[1]Marx Bros. Groucho
zeppi-Zp
100011
1033
[2]Marx Bros. Zeppo
gummi-Gm
100012
1036
[2] Marx Bros. Gummo
chici-Ch
100013
1039
[2]Marx Bros. Chico

prefixsymb valuevalue computer jargon usageorigin / plausible alternative
deci- d
10-1
10-1
[3] L. tenth "decimus"
centi- c
10-2
10-2
[3] L. hundred, hundredth "centum"
milli-m
1000-1
10-3
seldom used in jargonL. thousand "mille"
decimilli-dm
10-4
10-4
[4]  
centimilli-cm
10-5
10-5
[4] 
micro-µ, u
1000-2
10-6
[5] small or human-scale L. small "mikros"
nano-n
1000-3
10-9
even smaller, used for
RAM speed
Gk. dwarf "nanos"
pico-p
1000-4
10-12
even smaller yet It. tiny "piccolo"
femto-f
1000-5
10-15
not used in jargon - yet O.N. fifteen "femten"
atto- a
1000-6
10-18
not used in jargon - yet O.N. eighteen "atten"
zepto- z
1000-7
10-21
not used in jargon - yet L. ultimate letter z "zeta"
yocto-y
1000-8
10-24
not used in jargon - yetL. penultimate letter y "iota"
harpo-hr
1000-9
10-27
[1] Marx Bros. Harpo
groucho-gc
1000-10
10-30
[1] Marx Bros. Groucho
zeppo-zp
1000-11
10-33
[2] Marx Bros. Zeppo
gummo-gm
1000-12
10-36
[2] Marx Bros. Gummo
chico-ch
1000-13
1039
[2] Marx Bros. Chico


prefixsymb valuevalue
numerical value
origin / plausible alternative
kilo-K
10241
210
1,024
binary usage, common in computer science
kibi-Ki
10241
210
1,024
IEEE proposal
mebi-Mi
10242
220
1,048,576
IEEE proposal
gibi-Gi
10243
230
1,073,741,824
IEEE proposal
tebi-Ti
10244
240
1,099,511,627,776
IEEE proposal
pebi-Pi
10245
250
1,125,899,906,842,624
IEEE proposal, by extension
exbi-Ei
10246
260
1,152,921,504,606,846,976
IEEE proposal, by extension
zebiZi
10247
270
1,180,591,620,717,411,303,424
IEEE proposal, by extension
yobi-Yi
10248
280
1,208,925,819,614,629,174,706,176
IEEE proposal, by extension
[1] Not SI approved, Morgan Burke [1993] extension, Usenet approved.
[2] Not SI approved, Jargon extension of the Burke extension.
[3] Not SI approved, but in some common usage.
[4] Rarely used, not SI approved. Elicits head-scratching and laughs.
[5] The Greek mu µ is the highly preferred prefix.
NOTE regarding the status of the IEEE proposal: the Comite Consultatif des Unites decided 1995/1996 not to pursue the mebibyte and related units further at that time.

Computer jargon examples:
attoparsec (approximately = 3.1cm)
microfortnight (= 1.2096 sec)
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