Modals to express assumption: WILL, SHOULD, OUGHT TO

Present and future

Will and should + infinitive are used to express assumptions with reference to present and future time. Assumptions with will are more probable:

"The phone's ringing." "That'll be for me."
There's no point in speaking louder. He won't understand.
I should get back before 9.
"Is it far from here?" "I should think so."
"We're going to the Swiss Alps next week." "That should be nice."
I have never tried to set up a website, but it shouldn't be too difficult.

Ought to can be used instead of should, but it is less common:

Anne ought to be at home by now.

Past

Will, should and ought to + perfect infinitive are used to express assumptions about past events:

Some of you will have met me before.
The plane should have landed by now.