Zero, First and Second Conditionals

What are conditional sentences?

Conditional structures are often called ‘if clauses’, because they describe the result of something that happens, or may happen, or, in the case of ‘third conditionals’, something that ‘could have happened’.

What are the differences between Zero, First and Second Conditionals?

The chart below outlines the form and use of each with examples, however, it is important to keep these basic rules in mind:

Zero conditionals deal with facts and things which are generally true.
First Conditionals deal with things which are likely to happen.
Second Conditionals are used for things which are impossible in the present (If I were President ….) or things which are very unlikely in the future (If I won the lottery ….)

The form for each conditional follows a similar pattern. However, it can be reversed so that the result goes first and the condition goes second. We do not use a comma if the result goes first.

For example:

If I have time, I will help you. = I will help you if I have time.

The chart below outlines each conditional structure and is followed by some notes on the alternatives for each structure.

Zero Conditional

The Zero Conditional describes facts and things which are always or generally true. These could be scientific facts or things which are true for a particular person. For example:

If you boil water, it changes to steam.
If I don’t know something, I like to find the answer.

As with all conditional sentences, the clauses can be switched. If the result comes first, we do not use a comma.

The ‘if’ in the condition clause can generally be replaced with when, as in the examples above.

Also, the result clause could be replaced with an Imperative sentence, or an order. For example:

If you have any problems, call me.
If the printer isn’t working, don’t try and fix it yourself.

As you can see in the last example above, the Present Simple can be replaced with Present Continuous if that is more suitable. This is true for all other conditionals, where the Present Simple or Past Simple can be replaced with the continuous tense instead.

First Conditional

The First Conditional describes events which are (not) likely to happen in the future and the outcome. There are a number of things to note about the First Conditional.

As with all conditionals, the clauses can be switched. When the result comes first, the comma is not used.

We can use Present Continuous instead of Present Simple if it is more suitable, for example with longer actions or future plans. For example:

If he isn’t studying, he will fail his exams.
If we are taking the train, I will be much happier.

There are a number of alternatives to ‘if’ that can be used with first conditional. Some of these have no change in meaning, for example:

I will lend you the money, as long as you pay me back.
I will lend you the money, provided you pay me back.
I will lend you the money, on the condition that you pay me back.
I will lend you the money, but only if you pay me back.

We can also use unless to mean ‘if not’, which is the opposite of the regular first conditional sentence, so the will/ won’t must change to negative. For example:

If I have my work finished, I will go to the party.
I won’t go to the party unless I have my work finished.

If he studies hard, he will pass the exam.
He won’t pass the exam unless he studies hard.

We can use a modal verb instead of will/ won’t. This is usually might, to show we are less certain; could, to show a possibility, or should to show an expected result. For example:

If we leave now, we might get there on time. (it’s probable/ possible)
If we have some free time, we could take a walk on the beach. (it’s an option)
If he studies hard, he should pass his exam. (it’s the expected result)

The most common mistake students make when using the First Conditional is using ‘if + will’, this is wrong. Remember, the if and the will are in separate clauses.

For example:

~~If he will get the job, he will be happy.~~ ⮽
If he gets the job, he will be happy. ✅

Second Conditional

The second conditional describes ‘unreal’ or ‘imaginary’ situations. When we use it to talk about the present it is an impossible, imagined situation. Look at these examples from some famous songs:

If I were a boy, I would turn off my phone …… (Beyonce )
If I had a million dollars, well I’d buy you a house. (Barenaked Ladies)
If I could reach the stars, I’d give ‘em all to you. (Cher)
If I had the time, I’d stop the world and make you mine. (Noel Gallagher)

As with all conditionals, the clauses can be switched. If the result comes first, we drop the comma.

In the second conditional, we can use ‘were’ for all subjects, instead of was for singular. This is considered more formal. We often use this form when giving advice. For example:

If I were you, I wouldn’t tell him.
If I were you, I would see a doctor.

As with the First Conditional, we can use a modal verb instead of would to show less certainty. For example:

If I found a wallet, I might give it to the police. (Maybe, it’s probable/ possible)
If I found a wallet, I could keep the money. (It’s a possibility, an option)
If I found a wallet, I should give it to the police. (it’s the right thing to do)

The most common mistake students make when using the Second Conditional is using ‘if + will’, this is wrong. Remember, the if and the will are in separate clauses.

For example:

~~If I would have more free time, I would go to the gym.~~ ⮽
If I had more free time, I would go to the gym. ✅

First or Second Conditional?

Deciding which conditional to use, first or second, can cause problems for learners.

The most important thing to remember is that:

First conditional – the condition is likely, it could happen,
Second conditional – the condition is impossible or very unlikely to happen.

For example:

If I lose my job, I don’t know what I will do. (this is possible/ likely to happen)
If I lost my job, I don’t know what I would do. (this is imaginary, unlikely)

Sometimes there is very little difference, for small things which may or may not happen. For example:

If he took the train, he would arrive earlier.
If he takes the train, he will arrive earlier.

Both of these situations are possible, so we would probably use the First Conditional, but we may choose to use the Second Conditional with very little difference.