Gases vs. gasses

  • In modern English, the plural of gas is usually gases, and gasses is the simple-present verb. For instance, we might say that the more Bill gasses up his car, the more greenhouse gases his car emits. This isn’t a rule, though, and the plural gasses survives, appearing a small percentage of the time.


    The verb is so rarely useful (and its senses outside the phrasal verb gas up are no fun) that the rare instances of gasses we find on the web are mostly variants of gases. There is one of these for approximately every ten gases.



    Many scientists believe that carbon dioxide is one of the gases that contributes to the “greenhouse effect.” [Washington Post]

    Rotten-egg smell is a symptom of both septic gas, which leaks in through the plumbing, and toxic drywall, which off-gasses hydrogen sulphide. [National Post]

    The lights occur when ionised particles from the sun hit the Earth’s atmosphere and react with gases, in this case oxygen, which gives the red and green colours. [Irish Times]

    He regularly gasses up a private jet on Cavs off days during the season and flies to New York for events. [ESPN]


    1. this web site needs to be turned into kid talk so that anyone can understand it. you also need to fix the “starring or staring” box.

      • What do you mean? Which box needs to be fixed? If there is a display problem, please let us know what browser you are using so we can fix it.

      • Anonymous says

        Though this is late, I want to point out that this is a website about grammar, so if you can’t understand anything, you shouldn’t be here in the first place.

    2. I stumbled over ‘gasses’ while proofreading somebody else’s work. I was on the verge of changing it, then decided to consult a dictionary first. Looks like you should have done the same; both Webster’s (for AE) and Cambridge (for BE) list ‘gasses’ as an acceptable plural form.

      • This site is about reporting how English speakers use the language in the real word, and what dictionaries say doesn’t enter into it. We leave the dictionaries’ work to the dictionaries. What we write above is based on having looked at how writers treat “gas” in lots of different 21st-century texts from throughout the English-speaking world. What we found was thousands of instances of the plural “gases,” while nearly every instance of “gasses” we found was an inflection of the verb. Dictionaries aren’t useful for this sort of research because they are often behind the times, sometimes listing long-obsolete forms as still acceptable.

        • I’d totally use ‘gases’ myself.

          However, I think that calling the double-s variation a misspelling is going too far while it is still listed in major dictionaries. ‘Rare’, ‘unusual’, ‘technically correct but likely to make you look uneducated to the writers on this panel’ would be more appropriate in my opinion.

          Keep up the good work!

    3. A titular search at the US Patent Office reveals
      the “ss” variant in use since the 1920s and commonly used today. A
      full text search at (Society of Automotive Engineers) reveals the variant
      spelling in common use in peer reviewed papers for a similar expanse of time.

    4. A few minutes at lunch…

      I see that numerous titles on WorldCat use gasses as well. I cannot help but notice that some librarians have the temerity to label some of them with [sic] — fairly outrageous.

      I was a graduate student in linguistics.

    5. The Gasman says


    6. Gases? Now we are really catering to our Germanic roots. Gasses is clearly correct, in both plural and simple-present verb contexts. ‘Gases’ is essentially ‘gazes’ misspelled.

    7. Sutzuk ibn Loukoum says

      We need Hitler to explain this one. He’s both a grammarnazi and a gas-related systems expert.

    8. Liberty Valence says

      I would offer that “gases” refers to the plural form of the noun “gas”, a different word from “gasoline”, altogether, and “gasses” used as the verb form of “to gas”, as in chemical warfare, or riot control. “Gasses-up his car” would constitute a slang usage of the term, in my opinion, as “fuels” would seem to be the more correct word to use, in that case.

    9. Leif Ronnback says

      And what about, for instance, There were no clues as to the mystery gas(ses)(‘s) chemical makeup. Help.

    10. Joel Guidry says

      Unfortunately, if you follow the rules of English pronunciation, “gases” would be pronounced “gay-sez” as the e would cause the a to sound long. The s is doubled in both the verb and noun forms when adding -es to maintain the short a sound. I do understand that this site focuses on usage rather than prescriptive grammar, however this usage would actually change the pronunciation of the word in question.

      • You wrote, “I do understand that this site focuses on …” By your logic, “focuses” should be pronounced “foe-cue-sez”.

        • Sorry, i should have clarified. This rule applies to one syllable words and words where the accent (emphasis) is on the last syllable. “Focus/focuses” does not follow this rule as the accent is on the first syllable (FO-cus), not the last (fo-CUS).

          • OK, I’ll buy that. Thanks for the clarification. I still prefer “gases” to “gasses” and, in the same vein, “buses” to “busses”. Hard to teach an old dog new tricks.

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