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On Accident vs. By Accident

Ever wondered how prepositions can change the whole meaning of your sentence? Well, in the case of on accident and by accident, only one of them is the right way of using the phrase. In this article, let us figure out who wins – on or by!

1:47 min read
  Ramya Shankar  —  Grammar Tips
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By accident...

The correct phrase (adverb) to use traditionally, is: ‘by accident’. It means by mistake or something that’s done without the intention of doing it. For example, “she spilled the milk by accident.” We can also use the word ‘accidentally’ as a replacement for by accident – just two ways of referring to the same thing. Some other synonyms of the phrase include unintentionally or by chance.

More examples:

Do you think it is by accident that she got a double promotion?

I opened my mailbox by accident while checking something else and was surprised to see your mail.

Sometimes, what we do or say, even by accident, just backfires; so always be careful.

If I ever hurt your feelings, it was by accident; please let me know so I can apologize.

The glass slipped from my hand by accident.

On accident…

A far less commonly used variant of by accident - on accident, is almost exclusively used in the United States - and incorrectly so. Even there, no one uses ‘on accident’ in writing; it's only a spoken English term. In fact, it is considered incorrect to be used at all.

Now, some people tend to use on accident as they rationalize that it must follow a similar structure to ‘on purpose’ although the meaning is completely the opposite. Yet another cause of confusion is interestingly the word 'accident' itself!

On Accident vs. By Accident

The word accident can be an adjective as in the case: 

We had an accidental meeting.

And it can also be a common noun as in:

The head-on accident led to several injuries and two deaths.


There was no news report on the accident that happened yesterday.

Perhaps the preposition 'on' preceding the word accident is what causes people to use the phrase on accident instead of by accident.

If it is said – “The glass slipped from my hand on accident”, it just doesn’t seem or sound right.

As explained above, on accident is not commonly used as an adverb phrase, if at all. Whereas, ‘by accident’ is the only correct phrase to use when indicating an unintentional or accidentally carried-out action.

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  • whollygoats
    Do you think that is all on purpose....or, by accident?
    Why is 'on' correct when there is intention, but 'by' when there is not?
    LikeReply6 months ago
  • apzohvn
    I appreciate this discussion as I have said to many people, many times, for many years, that things are not done 'on' accident, rather, 'by' accident. So I would pose this question: Do you do things on mistake? LOL! No I do not think so. I'm sure you would say I do things 'by' mistake. Are not accidents and mistakes essentially synonymous? [Unpurposefully done] Therefore, they can only be said one way they are done "by".... 
    LikeReply 18 months ago
  • nuked_f
    I would love to post this all over social media. People who say on accident drive me crazy. The word "on" implies intention, whereas "by" more accurately describes something that has occurred without direct intention. Thanks 
    LikeReply 222 years ago
    • Soulwriter
      haha thanks to you too :)
      LikeReply 12 years ago
    • mrm.41166
      this answered my question better than the article. I wondered why it’s, “on purpose” and “by accident.”

      Thank you.
      LikeReply1 year ago
  • tcjessup
    Perhaps a logical reason why we say "on purpose" but "by accident" is this. "On" implies that things are going correctly (on course, on track, etc.), whereas "by" implies that they have gone astray (fell by the wayside, overcome by events). Thus, an intended outcome happens on purpose, an unintended one by accident (caused by an unanticipated event) or by mistake (caused by an error). 
    LikeReply 72 years ago
    • Soulwriter
      I tend to agree with you; well said.
      LikeReply2 years ago
  • DakotaWoods
    Thank you, U. Like you, I had not encountered the phrase in any context until recently. It came up (frequently) in a series of books I was reading and I thought it was the author's "mistake," or perhaps a quirk of hers. 
    LikeReply 22 years ago
  • U
    Sometime you can't worry about over-rationalizing the rules. This article tries to explain things and just makes it more confusing. Fact is, over 40 years and I've never even heard of "on accident" until maybe about 5 years ago. Not in school. Not on TV. Not in conversation. The first time I heard it I thought it was because the guy who said it grew up speaking Spanish and his grammar wasn't very good. Now I hear it everywhere here, even from teachers who should know better and it's driving me crazy. Don't know exactly how long ago it started but it's definitely grown to a point where the overwhelming majority of the population here seem to believe "on accident" is actually how it's said. I actually came here trying to find out if it's some kind of Californian expression or something but this article says United States? At least not where I come from thankfully. 
    LikeReply 12 years ago
  • DakotaWoods
    I don't understand what is meant by "both on and accident are used as independent words in sentences." This seems to be the crux of the explanation why "on accident" can't be used.
    LikeReply2 years ago
    • Soulwriter
      hmmm the phrasing there wasn't so clear. The article is out to explain that although, 'on accident' does in theory follow the same rules as 'by accident,' it is not 'correct English' and is not used in written English. 
      LikeReply2 years ago
  • mryba1988
    This article given no logical explanation for why "on accident" shouldn't work. What is the structural difference between it and "on purpose"? I don't see one. Simply claiming that it's different because it's different is no explanation at all.

    English prepositions are weird. Why "on a bus"? We ride in a bus, not on it. Using "on" to relate an action to an accident makes no less sense than using "by" or "though". If you're going to write an article chastising people for using the wrong preposition, offer something more substantial as a reason than "because I said so."
    LikeReply 22 years ago
    • Soulwriter
      I share your enthusiasm for grammar accuracy and I hear your complaint loud and clear! As you say, prepositions don't always make sense and come about due to common application that then become the rule. The English language is known to be riddled with contradictions and inconsistency! Not to mention, exceptions to the rules ;)

      I don't believe it's the author's intention to chastise - more to frankly emphasize what is and isn't in use in the instance of the phrase 'by accident.'

      Finally - you've got me thinking...perhaps the difference in prepositions is due to the active or passive nature of the words accident and purpose. 'On' purpose is an active act and intentional. 'By' accident is a passive act and unintended.

      This could also make sense with the phrases: 'On the road,' and 'By the wayside'.

      What do you think?
      LikeReply 62 years ago
  • emilyr.81851
    Since this is, I'll be pedantic. "Even there, no one uses ‘on accident’ in writing, its only a spoken English term." 1) This should be "it's," not "its." 2) Those clauses should be separated by a semicolon, not a comma; they are complete sentences. 
    LikeReply 52 years ago
    • Soulwriter
      Well-spotted! All corrected now. Thanks for that Emily!
      LikeReply 32 years ago
  • Jeffrey Norris
    Jeffrey Norris
    "As we see, on accident cannot be used as an adverb phase, both on and accident are used as independent words in sentences. Whereas, ‘by accident’ is the only correct phrase to indicate unintentionally or accidentally."

    In the above quote, the writer should have written the word phrase, not phase. While both words are legitimate English words, in the above setting, phrase would make sense whereas phase would not.
    LikeReply 53 years ago


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