The Grammar Guide Comma Do you need a comma after an adverbial infinitive phrase?

Do you need a comma after an adverbial infinitive phrase?

Do you need a comma after an adverbial infinitive phrase?

Infinitive phrases begin with an infinitive (to + the simple form of the verb), e.g. to be better, to win at tennis, to save money.

Infinitive phrases can function in a sentence as nouns, adjectives or adverbs. From a comma perspective you only need to worry about ones that function as adverbs. These are often found at the start of a sentence, but are not the subject.

  • Example: To be the best, you must practice.
  • Example: To read more, please subscribe to our newsletter.

When an adverbial infinitive phrase introduces a main clause then you should always follow it by a comma:

  • Correct: To be the best, you must practice.
  • Incorrect: To be the best you must practice.

But be careful that the phrase is not acting as a noun. Never put a comma after and adverbial phrase when "is" or "was" directly follows:

  • Correct: To be the best is his goal.
  • Incorrect: To be the best, is his goal.

When an adverbial infinitive phrase is found in the middle of a sentence you should surround it with commas. In this case, it is acting as an interrupter:

  • Correct: The suit, to be fair, suited him.
  • Incorrect: The suit to be fair suited him.
  • Incorrect: The suit, to be fair suited him.
  • Incorrect: The suit to be fair, suited him.

When an adverbial infinitive phrase finishes a main clause then you shouldn't use a comma before it:

  • Correct: The suit suited him to be fair.
  • Incorrect: The suit suited him, to be fair.

Common Questions about Comma