Conditionals: 14 Meanings of IF with SHOULD


The 14 meanings of should in a conditional sentence

Students can often be surprised or confused when they see ‘should’ in a conditional sentence, they have been taught the over-simplified 5 types of conditionals and not one of them has ‘should’ - but here it is!

There are 14 basic uses of Should in a conditional sentence, here I list them and afterwards I will look at each use in more detail:

    1 A possible obligation
  • If you are late, then you should sign the late register.
  • 2 Advice in a possible situation of what to do
  • If you are late, then you really should apologise!
  • 3 Advice in a possible situation of what not to do
  • If you want to be healthy, then you shouldn’t smoke
  • 4 A tentative conclusion
  • If they left their house at 9, then they should be here by now.
  • 5 A stronger conclusion if stressed
  • If they left their house at 9, then they SHOULD be here by now.
  • 6 A personal responsibility or duty, possibly moral, ethical or social
  • If someone is nice to you, then you should be grateful
  • 7 A perceived correctness, or incorrectness, of a situation
  • If there is no school today, then at least they should study.
  • 8 In the ‘IF Clause’ to set up a future possible “by chance” scenario
  • If you should see her, tell her to call me as soon as possible.
  • 9 A quite formal and polite request
  • If at all possible, I should like to make a phone call.
  • 10 Describe a recommended action in the past implying it didn’t happen
  • If he was late, he should have called (but he didn’t call)
  • 11 Describe an undesired action in the past implying it did happen
  • If he was late, he shouldn’t have entered class (but he did enter).
  • 12 As the past of Shall in unreal situations, or with a polite tone.
  • If you could do it that for me, I should be very grateful
  • 13 With “If I were you,” to give personal advice.
  • If I were you, I shouldn’t worry.
  • 14 Questioning a responsibility, almost rhetorically
  • If he was the one that was late, why should I care?

Let’s dive in and see some more details for each of the possible uses;

to dive in: to start an activity immediately

1 A possible obligation

If you are late, then you should sign the late register.

This use of should is one of the most common uses, indeed The Advanced Learner’s Dictionary has this as the first meaning of should [1]. It is similar to ‘what must be done’ but there are some differences, for example it could be considered slightly ‘weaker’, if you compare:

  • That carpet must be cleaned. (= It is absolutely necessary.)
  • That carpet should be cleaned. (= It would be a good idea.)
  • (From Swan [2])

And there is also the idea that perhaps the obligation will not be fulfilled. In the sense that it stays as a recommendation, but that the decision to do it is yours.

So in a way:

  • Must = These are your obligations, I am telling you to do them.
  • Should = These are your obligations, I am asking you to do them.

So here in the example, you are not breaking the rules if you do not “sign the late register” but you also not fulfilling your obligations as a student or worker etc.

I guess should is the grand-daddy of being passive aggressive!

passive aggressive: being aggressive but avoiding direct confrontation

2 Advice in a possible situation of what to do

If you are late, then you really should apologise!

Here again we have some recommended action for the other person, but again, there is the possible option that the speaker won’t be obeyed.

(More passive aggressiveness!)

This is the other main use of should, and really many of the following examples are specific versions of the two main rules, that of basically:

Should = Recommended obligation or suggestion, for you to do – “no pressure but...”

So here in the example, I am telling you what I would recommend you do ‘if you are late’ and..." of course what you do do is up to you… you know I am just saying you should apologise, you know...just sayin’...”.


3 Advice in a possible situation of what not to do

If you want to be healthy, then you shouldn’t smoke

Again, here the speaker is ‘recommending’ something, but again the agency is left up to the other person. The speaker is saying and “that’s your business”.

agency:(here) choice of action to take

Here specifically about 'should' in the negative Leech [3] says:

“the negative shouldn’t / oughtn’t to + Verb means that something isn’t right – and probably no one will put it right! E.g. I shouldn’t smoke so much. (but I do!)”


So in this example, if you use the negative form to yourself, you are basically giving advice to yourself which you are going to ignore. (Crazy!)

So in a conditional statement:

“If my boss doesn’t respect my free-time, then I shouldn’t really help him so much.”

Here there is little certainty that you will change your habits. Consider the far more direct “will not / won’t help him so much” which indicates a direct response given the condition. In other words "I will not help him so much! And that is final!"

Another interesting aspect to using should is that in a way it opens up a discussion to the other people you are talking to. You are not saying a definite plan with what you "will/would do", or what is simply possible with "can/could do" but rather - here is some advice to you or to myself – “and maybe you could tell me what you think?”


4 A tentative conclusion

If they left their house at 9, then they should be here by now.

This use concerns making logical conclusions concerning the facts that you have at hand – it might be purely objective and have no personal judgment. Be purely a question of logic. But it is also possible that a ‘heavier’ message could be implied in the tone.

(I say ‘heavier’ because the same wording “they should be here by now” could, of course, be used to convey “it was their duty/responsibility to be here by now” – but we look at that usage below.)

Swan [2] states that “Should can be used as a weaker form of must” in terms of making a logical conclusion.

And Huddleston & Pullam [4] define this as a “Medium modality” which they describe as so:

"There is a third category on the scale of strength which we call medium modality, though intuitively it is closer to the strong end than to the weak."


  • I) The meeting must be over by now.
  • II) The meeting should be over by now.
  • III) The meeting may be over by now.

Here ‘must’ means ‘definitely/certainly’. And ‘may’ just means it is simply a possibility. Should however sits in the middle but is stronger than a simple 50/50 chance.

So on the one hand, it is a medium-strong logical conclusion, but on the other hand it is not absolute, it is softer and leaves a lot of room for error.

There is another possibility here with the same phrases, and that is in spoken form if the should is stressed, we have a look at this next.


5 A stronger conclusion if stressed

If they left their house at 9, then they SHOULD be here by now.

So with the same wording BUT with a stress on the word should we can make the speaker sound more definite about the possibility.

But I would not go so far as to say that it is the same as ‘must’. If we compare the following three sentences (will, must and should):

“If he performs as well as he can, then he will pass the test.”

With ‘will’ we are simply saying that the result is a simple consequence, there is no prediction here.

“If he performs as well as he can, then he must pass the test.”

With ‘must’ we are drawing a strong logical conclusion, so strong in fact that ‘must’ is used here to eliminate even any possible doubt.

“If he performs as well as he can, then he should pass the test.”

Now with ‘should’ we have introduced some doubt. Using should introduces that it is not completely guaranteed. 'Should' in this sentence communicates a medium to strong belief that he will pass the exam - but there are things which may not go to plan. The idea that “It is up to someone else” as we talked about earlier.

Now we come to the stressed 'should'. The logic is the same but we are stressing what we believe to be the correct result - but we know that life doesn't always work out the way that is correct/best.

“If he performs as well as he can, then he SHOULD pass the test.”

So we are stating that our logical conclusion is even stronger BUT we are still leaving some doubt in the hands of the fickle gods. Something illogical could still interfere!

fickle: capricious, doing as they want with no particular logic or rational

6 A personal responsibility or duty, possibly moral, ethical or social

If someone is nice to you, then you should be grateful

Should has some quite heavy connotations.

It can make people angry to be told what they should do.

“Don’t you dare tell me what I should or shouldn’t do!”

And this is because of its “deontic interpretation” [4].

This fancy word refers to how the word should can be used to convey a person’s responsibility or their duty, or the expectations placed upon them, in terms of moral, ethical, practical or social ‘rules’.

As Huddleston & Pullam state:

Deontic should/ought is usually subjective, indicating what the speaker considers ‘right’ – whether morally (One should always tell the truth) or as a matter of expediency (We should buy now while the market is depressed ).

So there is the idea of ‘subjective’ rules which many people can find oppressive. But as they say when they continue:

{Should/Ought to} are weaker than 'must' in that they allow for non-actualisation: I should stop now but I’m not going to.

So strangely we have a situation where rules are being imposed on someone, but the rule giver is inferring that they might not actually be followed. “Sorry? What? Give me a better understanding here...”

So we can think of ‘Preaching’. Preaching is when someone tells you all about how you should live your life (their rules, the rules of a religion, or an organization etc) - but in a way, they are preaching exactly because you either don’t follow these rules or you need to be reminded all the time. Why else would you need to preach?

So this is where should can begin to be interpreted in quite a heavy way – we are made to feel ‘bad’ for not doing what is expected of us. Guilt trip!!!!

A guilt trip: the feeling felt when someone else makes you feel guilty

7 A perceived correctness, or incorrectness, of a situation

If there is no school today, then at least they should study.

This idea of rules that a person ‘should’ follow can be extended to rules a society ‘should’ follow too!

Some sort of unwritten or accepted or desired set of rules that should be adhered to.

Basically, “here is what is best to do” in this situation.

Leech [3] says that should represents a...:

“good thing to do: something that is right or desirable (but is probably not done at the moment) eg The government should lower taxes”

The ‘not done at the moment’ simply reiterates the idea that should is often used in a prescriptive way (or similar to deontic, or subjective) rather than descriptive.

And this usage can be applied on a micro or personal level.

As Huddleston & Pullam [4] say:

to say what we think it is right for people to do.

For example,

You should see ‘Daughter of the Moon’ - it’s a great film.[4]

This is still quite ‘heavy’ though because you are telling people what to do. Or if you are talking about people in general, how other people should be acting and living.



8 In the ‘IF Clause’ to set up a future possible “by chance” scenario

If you should see her, tell her to call me as soon as possible.

This use of should is different than the other uses because it is in the ‘IF Clause’ and not the resulting second clause.

So this is describing the condition itself. It means the same as ‘by chance’

For example:

  • If you should see an English newspaper, could you buy it?
  • If by chance you see an English newspaper, could you buy it?

And this usage can be used with inversion too:

  • Should you see an English newspaper, could you buy it?

However two things to note, firstly is that this is predominantly more common in British English, and secondly even in BrE its use is disappearing. However, you may see it, especially in novels that are not recent.


9 A quite formal and polite request

If at all possible, I should like to make a phone call.

Again this use is getting quite dated, although you will see it in old films and books.

The Advanced Learner’s Dictionary [1] does still list it and is simply termed a ‘polite request’.

The usage stems from 'should' and 'would' being in some circumstances the same conditional auxiliary. So, “If it is OK, I should like to….” is now just a dated version of “If it is OK, I would like to...” which is much more preferred in modern English.


10 Describe a recommended action in the past implying it didn’t happen

If he was late, he should have called (but he didn’t call)

Moving on to ‘should have’.

The use of should on its own for the past is not common, and ‘should have’ is preferred.

As Huddleston & Pullam [4] state, should on its own no longer has a meaning in the past:

“The modal remoteness meaning of the preterite is much more common with the modal auxiliaries than the past time meaning: should, indeed, is no longer used with the past time meaning”

So if we would like to use the idea of should in the past we typically use should have.

Leech [3] states that should have “implies that the event did not happen”.

And Swan [2] says should have (and ‘ought to’):

“can be used to talk about unfulfilled past obligations: things which weren’t done, or which may or may not have been done.

  • I should have phoned Ed this morning but I forgot.
  • Alice ought to have spoken to James, but I'm not sure she did.

And Huddleston & Pullam [4] go even further by stating that such a use (and in some cases when it is used in the present as well ‘convey criticism’):

With past or present time they are commonly used when it is known that the situation was/is not actualised, in which case they convey criticism: He shouldn’t have gone to bed so late ; You should be doing your homework instead of watching television.

So the idea here is a combination of “this is what didn’t happen” and I am telling you “what didn’t happen was actually the right thing to do”.

Here when we use should have we leave the passive aggressive use of should in the present to the know-it-all in hindsight heavy preacher!

This is when it is used in the positive and so, conversely, up next is the negative version...


11 Describe an undesired action in the past implying it did happen

If he was late, he shouldn’t have entered class (but he did enter).

So much as should have is to ‘complain’ about what didn’t happen, so shouldn’t have is to ‘complain’ about what did happen!

As Leech [3] says, shouldn’t have “implies that the event did happen.”

This is interesting because there is no speculation about what happened or not, merely an implied criticism (see previous meaning) of what we know happened and a judgment that it shouldn’t have.

For example:

Even if your brother hit you, you shouldn’t have hit him. (but you did)

NOTE: I use this example with a parent speaking in mind on purpose! The reason is that such criticism of past actions and "what would have been best to do and not do" is naturally typical of language used by a parent… and I should know!


12 As the past of Shall in unreal situations, or with a polite tone.

If you could do it that for me, I should be grateful

This is another use of should that is a little outdated and was originally from its use as a synonym of would. See the use of should for polite requests above.

In fact Leech [3] describes it simply as

Here should is polite and formal and it can be replaced by would.


13 With “If I were you,” to give personal advice.

If I were you, I shouldn’t worry.

Here you are simply giving your common or garden heavy handed advice with should… (I'm joking… well... maybe not.)

common or garden:normal, not special, ordinary

This use of should is simply an extension of other meanings, however, there are some additional notes here.

With the “If I were you” structure we often omit the “If I were you”.

So for example:

Oh! If I were you, I shouldn’t think too much about it.

Can and is often said as:

Oh! I shouldn’t think too much about it!

And a second note is that in American English they would typically not use should, and would use would. While in British English both are still ‘fairly’ common.

So this is probably the most common form today

Oh! I wouldn’t think too much about it!


14 Questioning a responsibility, almost rhetorically

If he was the one that was late, why should I care?

Finally, we have rhetoric uses of should in questions.

Swan [2] observes the following:

Why/How should . . . ?
Why should . . .? can be used aggressively to reject suggestions, requests and instructions.
‘Anna’s very unhappy.’ 'Why should I care?’
‘Could your wife help us in the office tomorrow?’ Why should she? She doesn’t work for you.'

How should/would I know? is an aggressive reply to a question.

‘What time does the film start?’ 'How should I know?

Note that these questions are indeed rhetoric and aggressive and if you were to answer you would probably find you are going to have your hands full for the next few minutes!!!


Wow, that was a long and often complicated article!

I hope it proves to be very useful!

All the best!
Adam!


References & Bibliography

1. Hornby, A.S..Oxford Advanced Learner’s Dictionary. Oxford University Press, Fourth Edition, 1989. Print. Specific sections Should (Lemma) and Must: Usage notes

2. Swan, Michael. Practical English Usage. Oxford University Press, Fourth Edition, 2016. Print. Specific sections: 69, 73, 76, 240, 244, 303

3. Leech, Geoffrey. The A-Z of English Grammar & Usage. Edward Arnold, 1989. Print. Specific sections “Should and Ought to” pages

4. The Cambridge Grammar of the English Language – Huddleston & Pullam Specific sections: p107, p177,

5. CAMBRIDGE GRAMMAR OF ENGLISH - Carter & McCarthy

Here are some links that could be of interest!

Check out: Using_In_Case_Should_Happen_To