What are Modal Verbs of Advice: Should & Ought To?
When we want to suggest that someone do something, recommend a course of action, or say what we believe is the right thing to do, English uses two main modal expressions: should and ought to. Both express a similar idea — that something is a good idea or the advisable course of action — but should is by far the more common, especially in speech.
Should and ought to express weak obligation or recommendation. They are softer than must or have to (which express genuine necessity) and stronger than could or might (which merely suggest a possibility). Think of them as the "it would be a good idea" modal — they express what is advisable, expected, or morally right, without demanding it.
One of the most important — and most tested — patterns built on should is should have + past participle. This form lets you talk about the past: what would have been the right thing to do, but wasn't. It is the grammar of regret and hindsight, and it unlocks a whole register of natural, reflective English.
How to Form Should and Ought To
Should is a true modal verb: it is followed directly by the base infinitive, never changes form, and forms negatives and questions without do. Ought to is a semi-modal — it also uses the base infinitive, but uniquely among modals it requires to before the main verb.
Subject + should / ought to + base verb · same form for all subjectsShould and Ought To — forms
| Form | Should | Ought to |
|---|---|---|
| Positive | You should rest. | You ought to rest. |
| Negative | You shouldn't wait. | You ought not to wait. |
| Question | Should I apply? | Ought I to apply? (rare — use should instead) |
| Past (regret) | I should have called. | I ought to have called. |
| Past negative | You shouldn't have said that. | You ought not to have said that. |
When to Use Modal Verbs of Advice: Should & Ought To
Giving advice — should / ought to
The most common use: suggesting to someone what they ought to do about a particular situation. The advice can be directed at a specific person ("you should") or framed as general guidance. Ought to is slightly more formal and objective — it implies something is the right thing to do by some standard, rather than just the speaker's personal opinion.
- You should see a doctor if that cough doesn't improve.
- You ought to call her and apologise — she's upset.
- He should apply for the job — he has exactly the right experience.
Expressing general best practice or recommendation
We use should and ought to to describe what is generally considered the right, wise, or correct approach — not a specific personal situation, but a principle that applies broadly. This is the modal of professional advice, health guidelines, and commonly accepted norms.
- You should always back up your files — it takes seconds and can save hours.
- Drivers ought to check their tyre pressure at least once a month.
- Children should get at least eight hours of sleep each night.
Expressing expectations — should
We also use should to say that something is expected or anticipated — that it is supposed to happen based on a plan, a norm, or a logical prediction. This is less about advice and more about what we consider likely or appropriate.
- The package should arrive by Thursday — I sent it two days ago.
- The meeting should only take about half an hour.
- This should work — I've double-checked everything.
Expressing criticism — shouldn't
The negative shouldn't (should not) is used to say that something is a bad idea, inadvisable, or wrong. It can describe present habits or choices the speaker disapproves of, or — in its past form — criticise actions that already happened.
- You shouldn't eat so much junk food — it's affecting your health.
- He shouldn't be so critical — it demoralises the whole team.
- They shouldn't have released the product before it was ready.
Expressing past regret or criticism — should have / shouldn't have
To talk about what was the right (or wrong) thing to do in the past — but didn't happen (or did happen) — we use should have + past participle and shouldn't have + past participle. This is the grammar of regret, reflection, and criticism after the fact.
- I should have studied harder — I knew the exam was going to be tough.
- We should have booked the restaurant in advance — now it's full.
- You shouldn't have said that to her — it was unkind.
Key Context Words and Phrases
Should vs Must / Have To
Both should and must / have to involve some degree of necessity, but they are very different in strength. Choosing between them signals how serious the obligation is — a wrong choice can sound either alarmist or dangerously casual.
Should — advice, recommendation (not compulsory)
You should wear a hat — it's quite cold today.
The speaker thinks it's a good idea, but there's no rule requiring it. The listener can choose not to.
Must / Have to — strong obligation or legal requirement
You must wear a hard hat on site — it's health and safety law.
This is not optional — it is a rule, law, or requirement. Failure to comply has consequences.
Should — a suggestion that can be ignored
You should try the fish — it's excellent here.
A friendly recommendation. The listener is completely free to order something else.
Must — genuine necessity or urgency
You must try this — it's unlike anything you've ever tasted.
Using must here adds emphasis and urgency — the speaker feels very strongly. The force is much higher than should.
Should Have vs Past Simple
A common point of confusion: learners sometimes use the past simple where should have + past participle is required to express regret or criticism. The two forms describe very different things.
Should have — regret about what didn't happen
I should have called before coming over.
I did not call — and I now think that was a mistake. The past participle after 'have' is required. This is a reflection on a missed action.
Past Simple — a statement of what happened
I called before coming over.
A neutral fact — I did call. No regret, no evaluation. Just the action that occurred.
Shouldn't have — criticism of what did happen
You shouldn't have spent so much on that.
You did spend the money — the speaker thinks it was a bad decision. The action happened; the criticism comes after.
Past Simple — a neutral report
You spent a lot on that.
Just a description of what happened — no judgment. The past simple carries no evaluation of whether the action was right or wrong.
Common Mistakes
Adding "to" after "should" (should + bare infinitive, no "to")
✗ You should to rest. / She should to call him.
✓ You should rest. / She should call him.
Should is a modal verb and takes the bare infinitive — no "to". The confusion often arises because "ought to" requires "to", leading learners to add it to "should" as well. Remember: "should + base verb" (no "to"), "ought to + base verb" (with "to").
Using "ought" without "to"
✗ You ought go now. / He ought leave earlier.
✓ You ought to go now. / He ought to leave earlier.
"Ought" always requires "to" — it is a semi-modal, not a true modal verb. Unlike "should", "must", "can", or "will", "ought" cannot be used without "to" before the main verb. If you find "to" difficult to remember, simply use "should" instead — the meaning is the same in most contexts.
Using "should" where "must / have to" is needed (strength mismatch)
✗ You should wear a seatbelt — it's the law.
✓ You must / have to wear a seatbelt — it's the law.
"Should" expresses advice — it implies the listener has a choice. For legal requirements, safety rules, or genuine obligations, use "must" (internal/authoritative) or "have to" (external rule). Saying "you should wear a seatbelt" about a legal requirement downplays the obligation and can sound misleading.
Using "should" without "have" for past regret
✗ I should study harder last year. / We should book the restaurant.
✓ I should have studied harder last year. / We should have booked the restaurant.
To talk about the past with regret or criticism, you need "should have + past participle". Without "have", the sentence is present or future — "I should study harder" means I ought to study harder now or in general, not that I regret not studying in the past.
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