All of a Sudden

Meaning of Idiom ‘All of a Sudden’

All of a sudden means abruptly, without any warning; unexpectedly.

All of a sudden is simply a more idiomatic and poetic way to say ‘suddenly.’

It tends to add emphasis to just how ‘sudden’ something was. Suddenly means quickly and unexpectedly.


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Usage Notes

English learners frequently make the mistake of saying this as ‘all of the sudden.’ You must use ‘a’ not ‘the.’

All of the sudden was used in the past, but it sounds entirely incorrect today.

All at once can be used in a similar sense but also has the additional meaning of ‘all at the same time.’

All at once will not always be interchangeable with all of a sudden. Reserve this idiom for something that would normally occur over a period of time but that instead occurred very quickly and unexpectedly.

For example, you would not say “All at once, the lights went out” because electric lights are either on or off.

They do not go off gradually. So, ‘all of a sudden, the lights went out’ would be more appropriate.

However, we are accustomed to darkness coming on gradually. During an eclipse, this happens suddenly. So, you could say ‘All at once, it was completely dark outside.’

Examples Of Use

“I was making dinner the other night and all of a sudden I heard a bunch of gunshots. Almost twenty! Turns out it happened only a mile or so away from my house.”

“I don’t know why she all of a sudden refused to talk to me. I didn’t do anything to her.”

“These headaches are the worst. Everything is fine and then all of a sudden my head is pounding.”

“Not a cloud in the sky and all of a sudden it starts raining.”


The earliest variations of this idiom were ‘of a sudden’ and ‘on a sudden.’ Of a sudden stuck and the word all was added later, during the late 1600s.


More Idioms Starting with A

More All Idioms

More Sudden Idioms


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