The First Conditional in English

The first conditional is one of the most useful grammar structures in English. We use the first conditional to talk about real and possible future situations and their results. In this lesson, you will learn how to form it, when to use it, and how it differs from the zero conditional.

We often use the first conditional to:

talk about possible future results
make predictions
give warnings
make offers and suggestions
talk about plans and decisions

Let’s look at how it works.

What is the first conditional?

The first conditional describes a future situation that is possible and realistic.

It means:

if one thing happens, another thing will probably happen as a result.

Examples:

If you eat that, you’ll be sick.
If she needs a car, she can borrow mine.
I’ll stay at home if it rains.

These situations are not imaginary. They are real possibilities in the future.

Structure

The basic structure is:

if + present simple, will + infinitive

will + infinitive + if + present simple

Examples:

If it rains, we will stay at home.
If you study hard, you will pass the exam.
She will be late if she misses the bus.

So, the sentence has two parts:

the if-clause (the condition)
the main clause or result clause (the result)

For example:

If I see Anna, I’ll tell her.

Here:

If I see Anna = the condition
I’ll tell her = the result

Important rule: present simple after if

In the first conditional, we use the present simple after if, not will.

✅ Correct:

If I see him, I’ll call you.

❌ Incorrect:

If I will see him, I’ll call you.

This is one of the most common mistakes learners make.

The comma rule

Use a comma after the if-clause when it comes at the beginning of the sentence.

Examples:

If it rains, we’ll cancel the picnic.
If you need help, just ask me.

But if the main clause comes first, we usually do not use a comma.

Examples:

We’ll cancel the picnic if it rains.
Just ask me if you need help.

A small comma, but an important one — punctuation likes order almost as much as teachers do.

When do we use the first conditional?

1. To talk about a real future possibility

If the weather is nice tomorrow, we’ll go to the beach.
If I finish work early, I’ll come with you.

2. To make a prediction

If you don’t hurry, you’ll miss the train.
If she keeps practising, she’ll improve quickly.

3. To give a warning

If you touch that wire, you’ll get an electric shock.
If you don’t wear a coat, you’ll get cold.

4. To make an offer or suggestion

If you like, I’ll help you with your homework.
If you’re tired, we can stay at home tonight.

Words and phrases we can use instead of if

Although if is the most common word in the first conditional, we can also use other linking words and phrases such as:

when
unless
as soon as
as long as
in case

When

Use when when the speaker sees the future situation as likely or certain.

When she arrives, we’ll start dinner.
I’ll call you when I get home.

Unless

Unless means if not.

We’ll go for a walk unless it rains.
You won’t pass unless you study.

As soon as

Use this to show that one thing will happen immediately after another.

We’ll start eating as soon as Julia arrives.
As soon as I finish this email, I’ll help you.

As long as

This means only if or provided that.

As long as you tell the truth, I’ll support you.
You can borrow my car as long as you drive carefully.

In case

We use in case when we do something because something might happen.

Take an umbrella in case it rains.
In case you don’t get back by ten, I’ll call the police.

The first conditional vs the zero conditional

Learners often confuse the first conditional and the zero conditional, so let’s make the difference clear.

We use the zero conditional for:

general truths
scientific facts
habits
things that are always or usually true

We use the first conditional for:

real and possible future situations
specific future results

Compare:

Zero conditional:

If I finish work on time, I always go out with my friends.
(This is a habit.)

First conditional:

If I finish work on time, I’ll go out with my friends.
(This is a particular future situation.)

Another example:

Zero conditional:

If you exercise, you burn fat.
(A general truth.)

First conditional:

If you exercise, you’ll burn fat.
(A likely result in a particular situation.)

So the zero conditional is general, while the first conditional looks forward to a real future possibility.

More examples

Here are some more examples to help you hear the pattern naturally:

If you invite me, I’ll come.
If they leave now, they’ll catch the train.
If he doesn’t apologise, she won’t forgive him.
If we have enough time, we’ll visit the museum.
If you’re hungry, I’ll make you a sandwich.
If the shop is open, I’ll buy some bread.

Common mistakes

1. Using will after if

❌ If it will rain, we’ll stay inside.

✅ If it rains, we’ll stay inside.

2. Confusing the zero and first conditional

❌ If you heat water, it will boil at 100°C.

✅ If you heat water, it boils at 100°C.

This is a general truth, so we use the zero conditional.

3. Forgetting that both clauses can change order

Both are correct:

If I see Tom, I’ll tell him.
I’ll tell Tom if I see him.

Final thoughts

The first conditional is essential for speaking and writing about the future in a natural way. We use it when a future situation is real and possible, and we want to show its likely result.

Just remember the pattern:

if + present simple, will + infinitive

Once you get used to it, the first conditional becomes quite straightforward — one of those bits of English grammar that looks serious at first, then turns out to be rather well behaved.

The First Conditional Exercise worksheet with mixed practice, sentence building, and a teacher’s answer key – download the PDF

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