By John Conway | March 2, 2010 1:47 pm

A physics student here at UC Davis, Austin Sendek, has launched a campaign to add another designator to the list of numeric SI prefixes such as kilo-, mega-, etc. to cover 1027: hella. For example, 1 hellagram would be 1027 grams, or 1000 yottagrams.

The term “hella” is one I first heard my sister-in-law utter in the context “that ski run was hella fun!”, which I immediately took as a shorthand for “a hell of a lot of”. I’ve since learned that it originated, reportedly, in San Francisco to mean just that, or “very” in general, as in “that tee shirt is hella awesome” – it’s not an uncommon utterance to hear here in northern California.

And, 1027 is hella big, to be sure. A hellasecond is ten billion times the age of the universe, and the mass of the earth is about 6 hellagrams.

It seems that hella is poised to go viral…there are nearly 24,000 fans of the facebook petition, and it even made the local news last night in Sacramento.

Who decides such things? The International Bureau of Weights and Measures, that’s who. They added yotta in 1991. Sign the petition to them at the facebook site!

  • Russell

    Dang-it! I had already proposed that the unit hella be 10^666. 10^27 is way to small.

  • Russell

    Oops, 10^27 is way TOO small.

  • http://theeternaluniverse.blogspot.com/ Joseph Smidt

    That’s hella awesome.

    @Russell, 10^666 would be cool to have this prefix.

  • Alex

    Well Giga was apparently invented by a poet, so this should be no problem:


  • http://www.NimbleBooks.com Fred Zimmerman

    This is going the wrong direction. It would be fa more logical to use scientific notation for everything more than 10^9.


  • yj

    I just hate this English-centrism. We should take back the old school Latin&Greek education. At least that would be neutral to non-English speakers. So, if you really want to use “hella”, come up with a nice Greek/Latin reasoning.

  • Mortoc

    Fred: it would depend on the context. It’s much easier to say, “a few terrabytes of data” than to use the scientific notation for the number of bytes.

  • max

    Hell no hella. I was born and raised in norcal, and I cringe every time I hear someone use hella.

  • TheSlat

    I think all of southern California just cringed with you max. haha.

  • Kaleberg

    I don’t know about “hella”. How about “heckuva”?

    Why does this remind me of the old Mad Magazine (#33) Potrezebie System of Weights and Measures? I believe their extreme terms were “farshimmelt” and “furshlugginer”, from the Yiddish for “not much of a” and “an awful lot of a”.

  • Jeff

    The hella prefix should always designate the prefix just beyond the latest “officially” designated prefix. Then by definition it is never officially designated.

    Otherwise, consistent with the Greek derivations of peta, exa, zetta, and yotta, the next prefix should be something like “enna” (or, say, “Nenna” to preserve a distinct abbreviation, ‘N’)

  • TimG

    If hella is 10^27, then what’s 10^-27 ? holla?

  • jester

    Is this a pun intended for Daniel’s post on HeLa? I guess the number of HeLa cells are far smaller than 10^27 though it is steadily increasing. 😉

  • Charles Evo

    After Hella, I propose the next largest category be called “Bigga”.

  • hmm

    I’ll support this IF the US starts using the metric system

  • Mike

    @yj #6
    You do know that the Greek name of Greece is Hellas, right?
    I think we’re done here

  • http://vacua.blogspot.com Jim Harrison

    Kaleberg in #10 mentioned the Potrezebie System of Weights and Measures. I can’t resist adding a footnote. That Mad bit was contributed by the adolescent Donald Knuth. I’ve often wondered if he thinks of it as the high point of his life since becoming one of the greatest gurus of computer science seems a bit anti-climactic after what have been a supreme moment of teenage nerd triumph.

  • Kevin Taniguchi

    Yes! Go UC Davis! That’s hella awesome! 😉

  • http://observatorio.info Koldito

    When I was a postdoc at UCSC, one of the grad students I used to hang out with proposed to create a new smoothie and call it a Hella Berry. That has a heckuva more chance of getting accepted.

  • Michael

    So how big do we get before we reach the “Yomomma”?

  • Pieter Kok

    Mike (#16), you beat me to it.

    I like Hella; it has just the right ring to it for its proposed purpose, and H is not used yet. Now if only I had a facebook account, I could sign that petition…

  • James

    I always heard hella way more from people from Sacramento, not San Francisco.

  • ObsessiveMathsFreak

    Not to be an elitist drip, but considering the events of the last decade, perhaps basic science terms should not be subject to the whims of the general public.

  • Chris Larson

    The Hecto 10^-27!

    @Mortoc Great new coining there! Terrabyte: A unit of data equivalent to the sum of information inherent in the planet Earth. :)

    This reminds me of a column written in the early ’90s, apologies for the lack of citation, I can’t remember who wrote the thing. In it, the author proposed the LoC as a unit subsequent to terabyte. This would represent 32 terabytes, which in his calculations approximated the (then) amount of data contained in the Library of Congress.

  • Katharine

    Not an ubergram?

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  • Fill

    The real problem is it’s almost impossible to oppose this without appearing a bore. I do think that one could invent a new prefix that is not so cringe-inducing while at the same time being fun.

  • HappyPig

    It’s been proposed…. Tom Weller wrote something very similar in his “Science Made Stupid” about 20 years ago.

    Powers of 10:
    12 (helluva-)
    9 (heckuva-)
    6 (lotsa-)
    3 (buncha-)
    1 (decca-)
    -2 (sexi-)
    -3 (silli-)
    -9 (banana-)
    -12 (doodoo-)

    cf: http://www.besse.at/sms/tables.html
    Amazon link: http://www.amazon.com/Science-Made-Stupid-Tom-Weller/dp/0395366461

  • Michael Kingsford Gray

    How about the Phuckofalot? (F)

  • Eugene


  • jimspice

    All I can think is Julianne Moore and 30 Rock.

  • http://www.canonicalscience.org Juan R.

    From the physics student blog “MakeHellaOfficial” that you link above Sean:

    “The SI prefix system has a major inconsistency, in that the first letter of the abbreviation for kilograms, kg, is not capitalized, while all other prefix abbreviations for quantities above 10^1 are (e.g. Gm (gigameters), TW (terawatts)). To rebel against the SI system, join me in capitalizing the K in Kg. There’s nothing more effective than fighting fire with fire (well, except fighting fire with water…).”

    The point missed here is that kg is *not* Kg, i.e. prefix K added to unit g. The SI unit is [kg]. This is why k is not capitalized, just for avoiding students confusion with real prefixes as in KJ where the unit is [J].

  • Wil

    By the way, “hella” started in Berkeley and migrated out from there. As a Berkeley native it infuriates me when people say that it “started” in SF.

  • rd

    Isn’t 10^27 a bronto?

  • KT

    Soon hella will fall out of favor and we will be stuck with an annoying prefix, besides acceptance will likely lead to many more petitions of this sort and I am not sure this is a good idea.

  • andyo

    I don’t think kilo is capitalized in any case, is it?


  • http://canonicalscience.org Juan R.

    My first mistake, I wrote “Sean” but the link was given by John.

    To andyo, you are completely right, the correct SI prefix is “k”.

    Probably k was chosen to avoid confusion with K the unit for temperature. For instance the molar gas constant is R = 8.1314 J/(Kmol) where K denotes Kelvin. Whereas kmol denotes kilo mol.

    Third mistake, the linked “MakeHellaOfficial” blog says that all other SI prefix abbreviations for quantities above 10^1 are capitalized. That is not true, the prefix for hecto is “h”.

  • Low Math, Meekly Interacting

    I’m all for the metric F-load (roughly 2.2 imperial F-loads) if anyone wants to nominate it.

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  • Jimbo

    3 things come to mind:
    a. This is nothing but a `name game’ for the sake of a new post.
    b. The IBWM could give a damn less about any facebook petition, as
    they are perhaps the ultimate collection of bureaucrats, comprising a secretive panel that makes dogmatic decisions affecting Intl. standards for scientific measurements, that proceeds with the speed of molasses in winter.
    c. This `hella’ fluff I think is pretty far down the metrological list of priorities.

    Priority #1 should be to reform the absurd MKS/cgs metric system into
    a unified gram-meter-second one, thereby dispensing with kilo- & centi-prefixes entirely.
    1 A.U. = 150 Giga-meters is far more logical than 150 Mega-Km.
    G -> 6.67E-14 m^3/g-s^2; h-> 6.625E-31 g-m^2/s; c is unchanged.
    Planck length & time are unaffected, but Planck mass is bumped up by 10^3, as are the Newton & Joule. No big deal. They could easily be redefined to accomodate the extra factor of 1000.
    Electromagnetic units would be unaffected, allowing the IBWM to heal the horrible rift between SI & cgs units that has cursed the teaching and understanding of EM for centuries ! Electrodynamic unit shifts could be compensated for by rescaling the coulomb & ampere in proportion to new values for Newtons & Joules.
    Surely, this accident of history can be cleaned up, and an aesthetic, unified metric system can be forged which is shorn of prefixes to define basic physical units.

  • Jimbo

    In my prev. post, to be sure, a more explicit example of the illogic of prefixes should’ve been stated as 1 A.U. = `15 Tera-centimeters’.

  • http://canonicalscience.org Juan R.

    To Jimbo, your examples

    1 A.U. = 15 Tera-centimeters

    1 A.U. = 150 Mega-Km

    are not SI valid because “multiple prefixes may not be used”


    You can use centimeters (cm), terameters (Tm), Megameters (Mm), kilometers (km), or gigameters (Gm) as in your first value (1 A.U. = 150 gigameters), but not combinations.

    Notice also, as andyo correctly pointed out, that the correct SI prefix for kilo is “k” and not “K”.

  • Jimbo

    Then how would U express 1 AU = 1.5E11m in centimeters ?
    Numerically, it would be 1 AU = 1.5E13cm in cgs, which cannot be expressed as simply as 150 Gm in mks. Magnitude x basic unit is clearer than
    Magnitude x prefixed unit.

    No one ever describes a 100 Gbyte hard drive in some ludicrous competing
    system of units as 100 Tera-`millibytes’. However, the current systems impose prefixed units only thru historical precedent. They are cumbersome in the extreme, and unnecessarily confusing.
    Both mks & cgs could & should be unified into g-m-s, devoid of prefixes in the basic units.

  • http://canonicalscience.org Juan R.


    The response to your question is 1.5E13 cm.

    Notice, however, that prefixes are used to avoid exponents. Thus, more standard expressions would be (1.5E11 m) without any prefix and only exponent or (150 Gm) without any exponent and only prefix.

    As already explained in the previous post, expressions as your “Tera-millibytes” are not SI valid.

    Also your 100 Gbyte hard drive example is invalid within the SI because G = 1000 M and *not* 1024 M. See the next link for details on binary prefixes


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