I'm learning modal verbs now and get in trouble with "need" one.

In my textbook it is said that:

don't need to == needn't -- present simple
didn't need to -- past simple
needn't have done -- present perfect

In some inexplicable reason I think that needn't have done sounds weird (may be because I haven't ever heard of such construction).

So my question is: Is there a sentence that equal to needn't have done but without the needn't part (like the past simple one)? Or everything is just fine with it and I shouldn't keep in mind?

5 Answers 5


Actually, all of the examples are a little weird. Need is very rarely used as a modal any more, and it's likely that you'll be able to go your entire life without ever encountering it in speech. It is sufficient that you be able to recognize and understand sentences like the above, but don't expect to use them much. Just treat need like any other verb:

Present: don't need to

Present perfect: haven't needed to

Simple past: didn't need to

Past perfect: hadn't needed to

That said, the three examples are grammatically correct, strictly speaking. The phrase needn't have done is a fine, though archaic, way of saying didn't need to have done...


When you write I don't need to, or I didn't need to, you are not using need as modal verb; you are using it as a normal verb.

Modal verbs are different from the normal verbs because:

  1. The verb doesn't take the -s for the third person.
  2. To negate a modal verb, you add not after the modal verb, even in the present and past tense.
  3. Many modal verbs cannot be used in the past tenses or the future tenses.

She can speak English correctly.
She should not be here, now.
She will can go with us.
She musted study very hard.

Using need as modal verb (need is used as modal verb only in negatives, or questions), you should write:

I need not [verb].
I need not have [past participle of the verb].

When need is used as modal verb, it is used to express necessity or obligation.

Need I say more?
I need not have worried.

When need is not used as modal verb (which happens most of the times), then it is used as in the following sentences:

I need to go, now.
I didn't need to know all the details.
I have not needed that for ages.

  • Well, need in positives is always a normal verb, correct?
    – zerkms
    Feb 12, 2011 at 15:36
  • Need in positives is always a normal verb. It is probable you will find need used as modal verb in very few cases.
    – apaderno
    Feb 12, 2011 at 16:22
  • "need" used modally really gives a nice impression of precision and slight sophistication. Needn't you know how to use it properly? :)
    – wazoox
    Feb 12, 2011 at 17:37
  • @wazoox: I do need ;-)
    – zerkms
    Feb 13, 2011 at 1:38
  • also thanks for question fixes, it is amazing that I did not make mistakes, except of decoration ones ;-)
    – zerkms
    Feb 13, 2011 at 1:39

The opposite of needn't have done is should have done

For example:

It's too late to call the bank. I should have done that earlier.

Which is opposite in sentiment to

I bought oranges yesterday! I needn't have done that today.

Which can be equally expressed as

I bought oranges yesterday! I didn't need to do that today.

  • +1 Wow, didn't expect to see that aspect of needn't raised here. Was losing the will to die reading so many answers without seeing it ... Sep 5, 2015 at 0:41

There is nothing wrong with "needn't have done". It means, simply, "did not need to do [something]." This is true even though the cases are different. The actions that have been accomplished were done in the past in both cases.

You paid my bill? You needn't have done that. I was fully prepared to pay it myself.

You paid my bill? You did not need to do that. I was fully prepared to pay it myself.

  • Yes, I can get the difference, I just wanted to get the some sentence to replace it with something more modern, like @JSBangs gave here: english.stackexchange.com/questions/12342/…
    – zerkms
    Feb 12, 2011 at 14:15
  • @zerkms: Then I sugges you show @JSBangs a little love by accepting his answer, or at least up-voting it.
    – Robusto
    Feb 12, 2011 at 14:17
  • I know how SE works (I'm 16k+ SO user) ;-) Thanks for your answers guys.
    – zerkms
    Feb 12, 2011 at 14:18

I'd like you to send the exammple of needn't to my e-mail for example:

1- Iam a student in a school . I'm very tired so I needn't work so hard . 2- He is a journalist . he is in his office. He can't write any report because he needs more truth information.
3- Jane is a secreatary .she can't answer the phone because her phone is out of order so she needs a telepnohe reepairer. etc...

  • The phrase looks strange at least "I'm very tired so I needn't work so hard". You're tired. So what? I'm also very tired but I need to work hard because I'm not rich.
    – zerkms
    Feb 19, 2011 at 10:53

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.