In South Asia, we tend to use "I think" when we are almost sure about something; or sometimes use it ironically like in example "I think you should have done this yesterday". "I guess", on the other hand, is used when the person is not sure himself like in "I guess you come here often".

Now as I talked to some North American people, I noticed that they use the two terms oppositely. That is, "I guess" when they are almost sure and "I think" when not. So I want to know which is the correct way to use these terms? Or are they just equivalent?

4 Answers 4


The difference is a qualitative one, not quantitative describing probability.

It varies by context, but typically, "I think" indicates that you're basing what you're about to say based primarily on knowledge, thought or experiences you had before the current situation, whereas "I guess" indicates that you're doing on-the-spot speculation at that moment. The presence of either word doesn't indicate a level of certainty (this is given by context, including the tone in which it is spoken.)


A: I need to go home soon. It's 11 PM now, when does the last train leave? B: I think it's at 10 PM. Let me check. Yeah, 10 PM. I guess you have to call a cab.

B uses "I think" because he's recalling information he had before, and uses "I guess" when he's doing an on-the-spot appraisal of the current situation.

  • 3
    I think you're right. But I guess you think that means I spent more time reading your answer and writing my first sentence than I did on this second one (which would have been true, only this one is taking a long time to actually write! :) Jul 4, 2011 at 23:49

In my experience, North American usage is closer how you describe South Asian usage. I think is much more affirmative than I guess.

More than the difference in affirmativeness, though, is the intent. I think X connotes that the speaker has given X conscious thought and consideration, and according to their best judgment, calculation, or recollection, X is true. It is important to note that someone's best judgment may not be close to 100% confident. 60% or so would be sufficient for I think (so in this way is different than the description of South Asian usage).

I guess is often used in phrases like I guess so or simply I guess, in response to an inquiry. When used this way, it means the speaker doesn't care much or hasn't really given it much thought, but doesn't have any strong reason to disagree.

So, I think stocks are a better investment than bonds indicates that the speaker honestly believes stocks are better than bonds. He may not be sure, but he has analyzed them and he would bet on stocks. I guess stocks are a better investment than bonds indicates that the speaker has either already observed that stocks are better than bonds (so he is quite certain that they are in fact better, but he didn't have to really think about it) or that he has been told that stocks are better, and that is good enough for him.

Finally, phrases like I would guess X or my guess is that X indicate conjecture. The speaker is saying "well, I don't really have sufficient information, but if I have to make a guess, my guess is X".


Just so that this is logged here:

In the Southern US, we actually have a spectrum of these verbs:

In the approximate spectrum from “gut emotional response” to “precisely calculated answer,” it would be approximately:

  • I suppose

    I have leapt to this conclusion, but haven't really thought about it, before this moment. This is often used in guarded responses, that a person feels they might have to retract in future.

  • I guess

    Based on some past experience, I am making a choice without much consideration to the matter. However, if I'm shown to be wrong, I will not be terribly surprised.

  • I reckon

    Based upon rules of thumb or approximations, or perhaps professional or trade skills, I have thought about this briefly and arrived at this decision — reckon implies “passing judgement” and attaches some personal pride to the results. If I reckon something to be one way, and I'm wrong, it's a point against my intelligence or observational skills; if I guess or suppose something, and am wrong, there is no point against my pride.

  • I figure

    Often used to mean the same as reckon, but implies slightly more calculation at work. I believe that my statement can be taken as factual.

  • I think

    Having considered this briefly, this is my decision. I have made a judgement of fact in this matter, and am unlikely to change it without new information becoming available.

  • I believe

    Unless something changes, I will continue to provide the same answer to this question. I am giving a statement of fact which should not require further validation.

Of course, ‘polite sarcasm’ is also a trademark of the South, so when faced with an opposing viewpoint, one might reply like so:

“I think the sky is green; don't you think it's a lovely shade of green, today?”

“Um … yeah, I guess. I had supposed it was a bit more blue, than green, though.”

“Well, I figure it must be green because of the streetlights.”

“I suppose you might see it like that. I still reckon it to be more blue, to my eyes.”


"I guess" can also be used observationally where "I think" would sound like you have no sense of the obvious.

For example, suppose you ask a friend to drive you to pick-up your car from in front of the bar where you left it last night. When you get there, the car is gone and you notice the place it was parked was marked as a tow-away zone during normal business hours.

If your friend says:

I guess you should have come earlier.

they are addressing the missing car, while gently admonishing you in a slightly empathetic to mildly sarcastic way. Ultimately, it is a 'softer' statement.

Whereas, if they said:

I think you should have come earlier.

you would possibly think your friend dense or perhaps even stupid as that is so obvious it would not need to be mentioned aloud.

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