Language of the Day: "Should" VS "Have To"

“Should” and “Have to” are some commonly mixed up modal verbs among my students, so today let’s clear up which one to use and why!

Both of these verbs are used a lot when we talk about work or study, because they are all about expressing obligation, certainty, and advice.

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Modal verb: Should

'Should' is a modal verb. Modal verbs give additional information about the main verb. 'Should' is used to talk about assumptions and to give advice. It is the past tense of modal verb 'shall.' For example:

He should have forgotten to take his travel mug.

She should ask Nina to help her.

Semi-modal verb: Have to

'Have to' is a semi-modal, which means it sometimes acts like a modal verb and sometimes acts like a main verb. 'Have to' is used to express necessities, obligations, certainty, etc. For instance:

I have to visit the dentist as soon as possible.

I had to redo everything because of his mistake.

But grammar is useless without a reason to use it!
Let’s explore WHY we use “should” and “have to”

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Talking about Necessities

When we want to express things we are obliged to do or need to do, we use 'have to.' Have a look:

I have to reply to his letter.

We had to take an oath in court.

Advice

We use 'should' to ask for and give advice. Advice is an opinion expressed about the right way to do something in a particular situation. For example:

When should I leave to take the early morning bus?

You should leave at 6 a.m.