All of a Sudden versus All of the Sudden

What is the Difference Between All of a Sudden and All of the Sudden?

When to Use All of a Sudden

All of a sudden is a popular idiom. It functions as an adverb in sentences, much like the word suddenly.

All of a sudden tends to describe something that took place unexpectedly or without warning.

The idiom all of a sudden is an adverb phrase, which means it modifies verbs in sentences. Since it means suddenly, some writers have a pet peeve of people who use it to describe actions that don’t actually happen suddenly.


When to Use All of the Sudden

All of the sudden is an incorrect formulation of the phrase all of a sudden. Given the fact that it’s not the correct spelling phrase, it is rarely used in print.


Summary

Is it all of a sudden or all of the sudden? All of a sudden is an idiom that functions as an adverb phrase. It has the same meaning as suddenly, which means quickly or unexpectedly.

All of a sudden is the correct spelling.

All of the sudden is a misspelling of the phrase.