“Had to” vs. “must have”

The modal verb must has two past tense forms: had to and must have. Which form we use depends on whether we want to express obligation or if we want to say how certain we are about the probability of something happening. 

This table below shows us the past tense of must and have to and when to use them.

Must, have to
present past
When expressing obligation, we say:
I must go.
I have to go.
When expressing obligation, the past of must and have to is always had to:
I had to wash my car yesterday .
We had to go to bed at 8 o’clock when we were kids.
When expressing a personal opinion about probability (deduction), we mostly use must to express that we feel something is true:

He must be fit if he can run 10 kilometres.
It must be great to be rich.
When expressing a personal opinion in the past, we mostly use must have, NOT had to:

He must have been fit.
He had to be fit.

It must have been great.
It had to be great.


  1. Gil Claeys - November 9, 2015, 1:39 pm Reply

    Greetings from Ann Arbor, Michigan.
    Must I need a Website to communicate with
    And this is my question:
    Is Must/Need still used in America English?
    If we can get thru this question, I will go on to
    asking you about Present Tense Narrative. Thanks.

    • Jesus Samaniego - April 21, 2016, 4:04 pm Reply

      Thanks you so much, for sharing that explanation.
      I sometimes have incovenients or confusion about must and have to.

  2. ezzahraoui - November 28, 2015, 11:10 pm Reply

    i have one
    must in the past:Must +have + past participle expresses a near certainty, a logical conclusion about a past almost always in the affirmative.We use must have to express that we feel sure that something was true in the past.

  3. ramesh chand sharma - February 8, 2016, 10:16 am Reply

    We had to be go to bed at 8 o’clock when we were kids. In this sentence i am not getting understand the use of the words ”had to be go”

    • Stuart Cook - February 8, 2016, 10:20 pm Reply

      It was a typing error, and has been corrected now to We had to go.

Leave a Reply

Your email address will not be published.

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>