1. This is not that fast a car
  2. Not that good an idea

Can someone confirm that this is correct? Or do I need an of?

Sentences like those don't make much sense in my native language. if I were to translate it from my native to English, it'd be something like not so good a car. Of course, trying to find the correlation between one's native language and English isn't always helpful, but I just have trouble understanding this construction although I use it a lot.

  • Looks good and is idiomatic. "Not so good..." is also fine. Not much more to add, really.
    – Mick
    Commented Oct 9, 2016 at 5:21
  • Alright good to hear. Is this something people use a lot? Also what exactly is the difference between this and the version without that? ( "This isnt a fast car") Is "This isnt that fast a car" the negative version of "such"? Or essentially "Not so fast a car" if this is even correct I dont know. Ok you said so is possible now what do people use more often? So or that? Commented Oct 9, 2016 at 5:26
  • "Not that" is used much less than "not so" but it is still readily understood. "This is not that fast a car" means that it's not slow, but it is possibly not as fast as one might like (or expect). "Not so..." has the same meaning.
    – Mick
    Commented Oct 9, 2016 at 5:35
  • Ok I have to aks one more thing. When you say "Not so" do you mean "Not so fast a car" or "This car isnt so fast" ? Commented Oct 9, 2016 at 5:38
  • You will hear colloquially in U.S. regional dialects: This is not that fast of a car and Not that good of an idea. This is informal and colloquial and accepted, but never used in formal (or even most informal) writing. Commented Oct 9, 2016 at 5:39

1 Answer 1


Not that fast a car.

Not that good an idea.

Both the sentencs are idiomatic and correct grammatically.

Some people also use of after an adjective in such a construction. For example, not that fast of a car, not that good of an idea. The usage of of sounds superfluous; so the sentences without of are better and more common.

  • books.google.com/ngrams/…
    – Khan
    Commented Oct 9, 2016 at 7:10
  • Adding "of" to those sentences sounds in my ears as bad as "would of" instead of "would have"
    – mplungjan
    Commented Oct 9, 2016 at 9:45
  • @mplungjan, I agree with you.
    – Khan
    Commented Oct 10, 2016 at 0:33

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .