If someone tells you that you look tired?

What do you say?

1- I haven't slept well.


2- I didn't sleep well yesterday.

4 Answers 4


You could say either one, though there is some difference between them.

I haven't slept well.

This does not indicate any timeframe. It is possible you did not sleep well for a day, week, month, etc.

I didn't sleep well yesterday.

Here we know it was only one day (yesterday).

  • does that applies to the situation of looking tired? I mean if it has some effects in the present time?
    – user37421
    Jun 9, 2015 at 5:46

1 I haven't slept well. 2 I didn't sleep well.

In 1 your sentence is an explanation of your present appearane. Your sentence refers to the present situation. In 2 you have in mind a thing in the past.

Both sentences could be used, but I think 1 would be more appropriate.

  • 1
    For me it would be either I haven’t been sleeping well or I didn’t sleep well [last night] or I suppose I haven’t slept well since the accident but I haven’t slept well on its own doesn’t quite work.
    – Jim
    Jun 9, 2015 at 14:35

You could say either.

"I haven't slept well" could mean that you didn't sleep well last night or for several nights. As another person explained, it doesn't imply a timeframe.

I would add that the seemingly similar phrase, "I haven't been sleeping well", actually means something different from "I haven't slept well." This is because "I haven't been sleeping well" has a timeframe. It implies that you haven't slept well in at least 3 or so days.

"I didn't sleep well yesterday" means that you only slept badly last night. Although this phrase isn't technically incorrect, and virtually every English speaker would understand it, I would suggest saying "I didn't sleep well last night" because this is more similar to what a native speaker might say.


I can't think of any time or way I would ever say "I haven't slept well." If it's been a problem for some time, I would use present perfect continuous:

I haven't been sleeping well.

If it was just the one sleep period, I'm simply say:

I didn't sleep well.

I might add "last night" (although it's already implied), but "yesterday" is odd, unless you are someone who sleeps during the daytime.

I believe that the difficulty with present perfect in the negative is that it is often used to mean you have never done something. For example:

I haven't seen the pyramids.

Means you have never seen them. So saying you haven't slept well could mean that you have never slept well in your entire life. But even if that's what you are trying to say, it's very ambiguous. It leaves me wondering what you mean, anyway. I might use the present perfect if I put an actual time boundary on it:

I haven't slept well, lately.

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