Q&A: ‘On accident’ vs ‘by accident’

Each week here at the Australian Writers’ Centre, we dissect and discuss, contort and retort, ask and gasp at the English language and all its rules, regulations and ridiculousness. It’s a celebration of language, masquerading as a passive-aggressive whinge about words and weirdness. This week, accidental tourists…

Q: Hi AWC, if I spill the milk, do I do it “by accident” or “on accident”? 

A: First of all, don’t cry about it. 

Q: Haha, sure. But then what?

A: We can help. And yes, it’s true that both “by accident” and “on accident” often get confused – but according to the Merriam-Webster dictionary, “by accident” is the one you should be using.

Q: But maybe that’s just for Americans!

A: Nope, this one is universal. If anything, it’s Americans that have a higher incidence of incorrectly using “on accident” especially in younger speakers (but we’ll get to that later).

Q: So why is it “by accident”?

A: Going way back to the Romans of the 4th century, the Latin ‘per accidens’ set the tone for using “by” as the correct preposition. It would go on to become the French ‘par accident’ – which is how it came to English.

Q: Fine, but then WHY do so many use “on accident”? That can’t be an accident!

A: Well it’s very intentional of course, but it’s wrong. And there is a particular culprit. 

Q: Ooooh I love a good villain! Who was it?

A: The phrase “on purpose”.

Q: Please explain.

A: Something lacking intent – such as a chance meeting – is what you’d describe as happening “by accident” rather than “by chance” or “by design”. So that fits nicely with what we’ve confirmed so far. 

Q: It does.

A: But there is another, more common way of saying something that’s done intentionally or by design – and that is “on purpose”. In this case, many people (incorrectly) assume the grammatical equivalent of it would be “on accident” – matching the prepositions.

Q: Hmmm, both make a good case! 

A: There IS no case! You have to remember that while “by accident” is only two words, it is still an example of an IDIOM – just like “once in a blue moon” or “barking up the wrong tree”. It gets a kind of language ‘diplomatic immunity’ – retaining its form throughout time. 

Q: Ah yes, idioms. The fossilised rock stars of language.

A: Indeed. We often forget that small idioms like this are littered throughout English – with a particular, baked-in way of saying them.

Q: So basically what you’re saying that “by accident” was no accident?

A: Exactly! It was a package deal we inherited from the French. Set in stone.

Q: Yeah okay, so let’s roleplay this. John and Jane are fighting over whether the toy was broken intentionally. John accuses Jane of doing it “on purpose”…

A: The correct phrase!

Q: Meanwhile Jane mirrors this by countering that no, it was broken “on accident”.

A: Incorrect, even though it sounds balanced in the heat of the moment.

Q: Hmmm, I don’t trust Jane. I think she did it intentionally. She’s always been jealous of John…

A: This “on” accident often happens in this kind of context – where “on purpose” is lurking in the conversation.

Q: So to answer the original question, I spilled the milk “by accident”?

A: You did. Curiously, there has been a study done that found despite “on purpose” and “by accident” living in harmony for centuries, something odd happened around 1970.

Q: They were doing a lot of drugs back then…

A: If you were born before 1970, the study found that you had no issue learning and using “by accident” alongside “on purpose” etc – it’s all you used. But if you were born after 1995 you now almost exclusively use “on accident”!

Q: What about those born between 1970 and 1995?

A: A combination of both, but likely still favouring “by accident”.

Q: So why has this happened?

A: No one’s entirely sure – or why it didn’t become “by purpose” instead. But with the rise of the internet around the same time, it has taken hold fast.

Q: Despite being wrong?

A: Yep. Although, language is ever shifting and it may not be considered “wrong” in the future. By the way, one other theory of why it might have arisen is simply from a mishearing of “an accident”. For example, “Breaking the toy was an accident” – with the “an” somehow conflated to “on”.

Q: Sounds a bit unlikely.

A: It certainly doesn’t explain why it’s only a recent change, so we’d tend to agree there. 

Q: So to recap, I should always use “by accident” – and to use “on accident” would be an accident.

A: Haha, exactly. Or avoid it altogether by replacing it with the adverb “accidentally”.

Q: I just thought of an even better way to avoid it.

A: What’s that?

Q: Never have an accident in the first place…

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