SI prefix

An SI prefix is a prefix, that, when applied to a word, means to multiply that word by a particular power of ten. Examples of applications of SI prefixes include kilometer, megapixel, and gigabyte.

The standard large and small SI prefixes are given below.

Name	Value	Factor/Divider	Name	Value
deca-	10	ten	deci-	0.1
hecto-	100	hundred	centi-	0.01
kilo-	1000	thousand	milli-	0.001
mega-	106	million	micro-	10-6
giga-	109	billion	nano-	10-9
tera-	1012	trillion	pico-	10-12
peta-	1015	quadrillion	femto-	10-15
exa-	1018	quintillion	atto-	10-18
zetta-	1021	sextillion	zepto-	10-21
yotta-	1024	septillion	yocto-	10-24

Extensions

Andre Joyce's extension

Andre Joyce fabricated an extension to the system, noting that zetta and yotta seem related to sette (Italian "seven") and otto (Italian "eight.") Following the reverse-alphabet pattern, we have xova- \(= 10^{27}\), x + nove, and weica- \(= 10^{30}\), w + dieci. (The last letter has been changed to a to keep the pattern.) The pattern for the corresponding negative exponents, like deci-, centi-, and milli-, all end in -i.

From here, only the first syllable of the Italian number is used. We have:

• vunda- = \(10^{33}\), v + und(ici), vundi- = \(10^{-33}\)
• uda- = \(10^{36}\), u + (do)d(ici), udi- = \(10^{-36}\)
• treda- = \(10^{39}\), t + tred(ici), tredi- = \(10^{-39}\)
• satta- = \(10^{42}\), s + (qu)att(ordici), satti- = \(10^{-42}\)
• rinda- = \(10^{45}\), r + (qu)ind(ici), rindi- = \(10^{-45}\)
• qeda- = \(10^{48}\), q + (s)ed(ici), qedi- = \(10^{-48}\)
• pica- = \(10^{51}\), p + (d)ic(iasetta), pici- = \(10^{-51}\)
• oca- = \(10^{54}\), o + (di)c(iotto), oci- = \(10^{-54}\)
• nica- = \(10^{57}\), n + (di)c(iannove), nici- = \(10^{-57}\)
• menta- = \(10^{60}\), m + (v)ent(i), menti- = \(10^{-60}\)

The system continues to zotta- = \(10^{255}\) and zotti- = \(10^{-255}\).

Jim Blowers' extension

Initially Jim Blowers, like Andre Joyce, followed reverse-alphabet pattern and extends his system up to vigintillion:

• xona- = 10²⁷
• weka- = 10³⁰
• vunda- = 10³³
• uda- = 10³⁶
• treda- = 10³⁹
• sorta- = 10⁴²
• rinta- = 10⁴⁵
• quexa- = 10⁴⁸
• pepta- = 10⁵¹
• ocha- = 10⁵⁴
• nena- = 10⁵⁷
• minga- = 10⁶⁰
• luma- = 10⁶³

However, recently he changed this system and proposed his own system of prefixes up to 10³⁰⁰⁰. Here is a list of his prefixes:

• nina- = 10²⁷
• tena- = 10³⁰
• tenakilo- = 10³³
• tenamega- = 10³⁶
• tenagiga- = 10³⁹
• tenatera- = 10⁴²
• tenapeta- = 10⁴⁵
• tenaexa- = 10⁴⁸
• tenazetta- = 10⁵¹
• tenayotta- = 10⁵⁴
• tenanina- = 10⁵⁷
• bitena- = 10⁶⁰
• bitenakilo- = 10⁶³
• quadtena- = 10¹²⁰
• huna- = 10³⁰⁰
• tousa- = 10³⁰⁰⁰

Hella-extension

Austin Sendek, a University of California student, started a (somewhat jocular) Facebook petition to make "hella-" the official SI prefix for 10²⁷. "Hella" is a slang term originating out of Northern California, meaning "a lot of" or "very". The term has not become official, but both Google and Wolfram|Alpha have adopted it into their calculator systems.

Other extensions

There are many other extensions to the SI prefixes, which are listed on the wiki's articles on extended SI prefixes - for example, see the article Prefix 10^27.

See also

Googological affixes

Suffixes: -teen · -ty · -plex · -illion · -yllion · -exian · -chime · -toll · -gong · -bong · -throng · -illiob
Prefixes: gar- · fz- · fuga- · megafuga- · booga- · trooga- · googo- · googolple-
SI prefixes: deca- · hecto- · kilo- · mega- · giga- · tera- · peta- · exa- · zetta- · yotta- · ronna- · quetta-
Non-SI prefixes: 1.001 · 1.01 · 1.1 · 1.5 · 2 · 3 · 666 · 10⁴ · 10⁵ · 10⁷ · 10⁸ · 10¹⁰ · 10¹¹ · 10¹³ · 10¹⁴ · 10¹⁶ · 10¹⁷ · 10¹⁹ · 10²⁰ · 10²² · 10²³ · 10²⁵ · 10²⁷ · 10²⁸ · 10²⁹ · 10³⁰ · 10³¹ · 10³² · 10³³ · 10³⁴ · 10³⁵ · 10³⁶ · 10³⁹ · 10⁴² · 10⁴⁵ · 10⁴⁸ · 10⁵⁰ · 10⁵¹ · 10⁵⁴ · 10⁵⁷ · 10⁶⁰ · 10⁶³ · 10⁶⁶ · 10⁶⁹ · 10⁷² · 10⁷⁵ · 10⁷⁸ · 10⁸⁰ · 10⁸¹ · 10⁸⁴ · 10⁸⁷ · 10⁹⁰ · 10¹⁰⁰ · 10¹²⁰ · 10¹⁵⁰ · 10¹⁸⁰ · 10²¹⁰ · 10²⁴⁰ · 10²⁷⁰ · 10³⁰⁰ · 10⁶⁰⁰ · 10⁹⁰⁰ · 10¹²⁰⁰ · 10¹⁵⁰⁰ · 10¹⁸⁰⁰ · 10²¹⁰⁰ · 10²⁴⁰⁰ · 10²⁷⁰⁰ · 10³⁰⁰⁰ and higher