The phrase

to boil down to something

can be found in most dictionaries. However, to me, it sounds colloquial to write

Finding an exact solution to Eq. 1 boils down to ...

A real-life example can be found here, and many more here. Interestingly, many of the examples are by non-native speakers.

Is it good style to use this phrase in formal writing?

(I am prepared to hear that if people use it, then it is OK.)

  • 2
    It's fine in conversation, and in emails, but I would discourage its use in formal papers. Kris's answer is the correct one, although it would have been more helpful if he/she had suggested a suitable alternative.
    – Mari-Lou A
    Commented Oct 26, 2014 at 10:27
  • 2
    I don't agree that it should never be used -- ISTM there are contexts where this idiom captures something that a more strict formulation omits -- but some formal alternatives might be (depending on context): is equivalent to, reduces to, may be approximated by, requires...
    – walkytalky
    Commented Oct 26, 2014 at 10:57
  • 7
    If you're writing a formal article on chemistry, it could probably be interpreted in all sorts of ways... :-) Commented Oct 26, 2014 at 13:43
  • 3
    If, for example, you were writing for a scientific journal that would be read by both native and non-native speakers, it would be best to avoid using phrasal verbs, cliches, idioms, acronyms etc. many non-native speakers will find themselves puzzling over their meaning and might interpret them in a literal way (see rand al'thor's comment). If the readership consists solely of native English speakers, or it is restricted to a small group, you can use this type of phrasal verb but it might still come across as being "colloquial" and unprofessional sounding (IMNSHO).
    – Mari-Lou A
    Commented Oct 26, 2014 at 15:35
  • 3
    Scientific writing and formal writing use different guidelines. Commented Oct 26, 2014 at 17:44

7 Answers 7


As has been suggested in other answers, it is not very suitable in formal writing. Here are some alternatives you might consider:

  • amount to

  • be reduced to

  • be a matter of

  • be in essence

  • 1
    +1 for reduce as in and thus the above definition reduces to the following: Commented Oct 26, 2014 at 15:23
  • 5
    I think that it is suitable for formal writings. However, these phrases listed above are definitely preferred. Commented Oct 26, 2014 at 23:17

Boil down to is not informal. It can be used even in formal writing.

  • 2
    I've seen it several times in very well written mathematical papers.
    – egreg
    Commented Oct 27, 2014 at 15:10

The aim of scientific writing is to be clear and precise, not to be pretentious or highfalutin. There is absolutely nothing wrong with using the phrase to boil down. You could also say distill; it makes no difference.



Do not use cliches, catch-phrases, metaphors, slang words … in formal writing.

  • and avoid where possible phrasal verbs.
    – Mari-Lou A
    Commented Oct 26, 2014 at 10:50
  • 4
    I don't agree. I think I've seen this term in scientific articles. Though I am not native speaker, I agree with the opinion of Jasper.
    – Tomas
    Commented Oct 26, 2014 at 11:24
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    @Tomas The phrase is certainly used, but the question is if it is good style to do so. Commented Oct 26, 2014 at 11:37
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    As I am not your downvoter, I can comment freely. This is terse advice with little explanation and no alternative provided. But I wonder: which of “cliché, catch-phrase, metaphor, or slang word” do you consider this use of the phrasal verb boil down? The OED doesn’t say it is any of those things. Rather, it gives the primary sense of boil down as “to lessen the bulk of (anything) by boiling”, along with a figurative sense of “to condense, epitomize”. I presume you object to the common figurative sense used here as inappropriate to the register of a formal research paper. Please expand.
    – tchrist
    Commented Oct 26, 2014 at 15:12
  • 1
    @Mitch I explained in the comments above. Basically, non-native speakers have difficulty in deciphering many phrasal verbs. A writer risks alienating his readership if he's not careful or absolute certain that the PV is universally understood e.g. take off (common) vs hang about (confusing)
    – Mari-Lou A
    Commented Oct 28, 2014 at 17:24

@PainfulEnglish, your question prompted me to research for both of us and anyone else interested. I am writing a science fiction novel and want the science sections as realistic and believable as possible. Following are links to three short papers I found valuable.

"Introduction to Journal-Style Scientific Writing"

  • Do not use colloquial speech, slang, or "childish" words or phrases.

  • Do not use contractions: for example, "don't" must be "do not" and "isn't" must be "is not" etc.


"Guidelines for Writing a Scientific Paper" http://www.sci.sdsu.edu/~smaloy/MicrobialGenetics/topics/scientific-writing.pdf

"Word Usage in Scientific Writing" http://www.ag.iastate.edu/aginfo/word_usage.php


If there is something about the metaphor of boiling down that is appropriate, you might consider the more scientific term distills.

On the other hand, you might want to be more direct and less metaphorical if you are writing a scientific paper.


It might be better in a verbal presentation, where it's more personal and no matter how formal the environment is, an expression like that is good because of its simplicity.

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