First Conditional in English

In Brief

Use the first conditional for a future situation that you see as real or possible: if + present simple, will + base verb. For example, If it rains, I'll stay home. The condition can come first or second, but English normally does not use will directly after if in this pattern.

Overview

The first conditional connects a possible future condition with its likely future result. A condition is something that must happen before another result becomes possible. In If you leave now, you'll catch the train, leaving now is the condition and catching the train is the expected result.

This pattern is usually introduced at B1 because it combines familiar present-tense forms with the future form will. It is useful for plans, warnings, promises, offers, predictions, and practical advice. Although it is called the “first conditional,” the important point is meaning: the speaker treats the condition as a genuine possibility, not as an imaginary situation.

The two parts are called clauses (groups of words containing a subject and a verb). The if-clause gives the condition; the main clause gives the result. Either clause can come first without changing the basic meaning.

How It Works

The core pattern

Part	Form	Example
Condition	if + present simple	if the shop is open
Result	will + base verb	we'll buy some bread
Complete sentence	either clause can come first	If the shop is open, we'll buy some bread.

A base verb is the unchanged dictionary form, such as go, call, or be. After will, do not add -s, -ed, or to: will go, not will goes or will to go.

The present simple in the if-clause refers to future time here. It does not mean that the condition is happening now:

• If Maya finishes early tomorrow, she'll join us.
• We'll order dinner if nobody wants to cook.

Clause order and punctuation

Both orders are natural:

• Condition first: If you study hard, you'll pass.
• Result first: You'll pass if you study hard.

When the if-clause comes first, put a comma after it. When it comes second, a comma is normally unnecessary. In speech, clause order often reflects what the speaker wants to present first. The condition-first order sets the scene; the result-first order often highlights the result.

Positive, negative, and question forms

Either clause can be negative:

• If I don't hear from them, I'll call tomorrow.
• If the weather gets worse, we won't drive tonight.
• I won't go unless you come.

To ask a question, put the question structure in the main clause:

• What will you do if the flight is cancelled?
• Will they refund us if the event doesn't happen?

The if-clause keeps normal statement word order. Do not write if will the flight be cancelled.

Results with other modal verbs

Will is common, but it is not the only possible result. A modal verb is a helper verb such as can, might, or should that expresses ability, possibility, permission, or advice.

Main-clause form	Typical meaning	Example
will	expected result, decision, or promise	If you call tonight, I'll answer.
can	ability or permission	If you finish early, you can leave.
may / might	uncertain possibility	If traffic is heavy, we might be late.
should	advice or recommended action	If the pain continues, you should see a doctor.
must / have to	necessity	If the alarm sounds, you must leave immediately.
imperative	instruction or request	If you see her, tell her the news.

A question can also use a modal: If you see her, can you tell her? This is a request based on a possible future event.

Unless: “if not”

Unless introduces a negative condition and usually means if ... not:

• I won't go unless you come. = I won't go if you don't come.
• Unless we leave now, we'll miss the bus. = If we don't leave now, we'll miss the bus.

Because unless already contains a negative meaning, the verb after it is usually positive. Say Unless you hurry, not Unless you don't hurry, when you mean “if you do not hurry.”

Unless does not replace every instance of if ... not. It works best when there is one clear exception to a general result. I don't know if he isn't available expresses uncertainty about his availability; replacing if with unless would change the structure and meaning.

When, as soon as, before, and until

English also uses a present form—not will—after future-time words such as when, as soon as, before, and until:

• When I arrive, I'll text you.
• As soon as the meeting ends, we'll leave.
• I'll check the address before I send the parcel.
• We won't begin until everyone is ready.

Use if when the event is uncertain: If Leo calls, I'll tell him. Use when when you expect the event to happen and are talking about its timing: When Leo calls, I'll tell him. The choice shows the speaker's view; when is not a logical guarantee that the event will occur.

Examples in Context

English	Meaning in plain English	Note
If it rains, I'll stay home.	Rain is possible; staying home will be the result.	Basic prediction
If you study hard, you'll pass.	Studying makes passing likely.	Encouragement
We'll have a picnic if the weather stays dry.	Dry weather is the condition for the picnic.	Condition second; no comma
If I don't finish today, I'll continue tomorrow.	Not finishing today leads to more work tomorrow.	Negative condition
If you touch that pan, you'll burn yourself.	Touching the pan is likely to cause a burn.	Warning
I won't go unless you come.	Your coming is necessary for me to go.	Unless = if ... not
Unless we book soon, we won't get a table.	We need to book soon to avoid losing the opportunity.	Negative condition
If you see her, can you tell her?	Please tell her if the opportunity occurs.	Request with can
If the train is delayed, we might miss the start.	Missing the start is possible, not certain.	Might weakens certainty
If you feel dizzy, you should sit down.	Sitting down is the recommended action.	Advice with should
If the light turns red, stop.	A red light triggers the instruction.	Imperative result
When I get home, I'll make dinner.	I expect to get home; dinner follows.	When for an expected event
I'll call you as soon as I know the answer.	The call will happen immediately after I learn the answer.	Future time clause
What will you do if they say no?	The question asks about the result of a possible refusal.	Question in the main clause

Common Mistakes

Using will after if for an ordinary future condition

• Wrong: If it will rain, we'll cancel the match.
• Right: If it rains, we'll cancel the match.
• Why: In a normal first conditional, the if-clause uses a present form even though it refers to the future.

Forgetting the base verb after will

• Wrong: If she practises, she will improves.
• Right: If she practises, she will improve.
• Why: A modal such as will is followed by the base verb, without third-person -s.

Using would for a real future possibility

• Wrong: If I have time tomorrow, I would help you.
• Right: If I have time tomorrow, I will help you.
• Why: Will presents the condition as a real future possibility. Would normally belongs to a hypothetical pattern: If I had more time, I would help you.

Adding an unnecessary negative after unless

• Wrong: Unless you don't wear a coat, you'll be cold.
• Right: Unless you wear a coat, you'll be cold.
• Why: Here unless already means “if you do not.” The wrong version logically suggests the opposite of the intended warning.

Putting question order inside the if-clause

• Wrong: What will you do if will they cancel the flight?
• Right: What will you do if they cancel the flight?
• Why: The if-clause uses statement order and the present simple. Only the main question takes question order.

Using a comma in the wrong clause order

• Less standard: I'll call you, if I need help.
• Standard: I'll call you if I need help.
• Why: A defining condition after the main clause normally has no comma. Use one when the condition comes first: If I need help, I'll call you.

Usage Notes

Contractions are extremely common in conversation and informal writing: I'll, you'll, she'll, we'll, and won't. Full will not may sound more deliberate or emphatic. Be careful with 'll after names and nouns: Sam'll call is possible in speech, but Sam will call is often clearer in writing.

The first conditional does not state a precise mathematical probability. It presents the condition as open and realistic from the speaker's perspective. If the team wins, we'll celebrate does not tell us how likely a win is; it tells us that the speaker considers it possible and has a plan for that outcome.

In instructions and agreements, the result may be a command, permission, or obligation rather than a prediction: If a customer asks for a refund, contact your manager. This is still closely related to the first conditional because a possible future condition controls what should happen next.

Beyond the Basics / Advanced Use

Present continuous and present perfect in the condition

The core beginner pattern uses the present simple, but other present forms are possible when their meanings are needed:

• If you're working late tonight, I'll bring you dinner. The present continuous describes an arranged or temporary activity.
• If you've finished by six, we'll go out. The present perfect focuses on completion before a future point.

The broader rule is therefore a suitable present tense in the condition, not “present simple in every possible sentence.”

Will inside an if-clause

The usual rule against will after if has meaningful exceptions. Will can express willingness, a polite request, or insistence rather than a neutral future fact:

• If you'll wait here, the doctor will see you shortly. Here will means “if you are willing to wait.”
• If you will keep interrupting, we won't finish. Stressed will expresses persistent, often annoying behaviour.

These uses do not contradict the core pattern: will is adding its own modal meaning, not simply marking future time.

First, zero, and second conditional

Pattern	Example	Speaker's perspective
Zero conditional	If you heat ice, it melts.	General fact or regular result
First conditional	If the ice melts, the drinks will get warm.	Open future possibility
Second conditional	If we had more ice, the drinks would stay cold.	Imagined, remote, or contrary situation

Real speech does not always fit neat textbook labels, but this contrast helps you choose between will and would. Focus on how the speaker presents the situation, not only on whether it is objectively likely.

Formal alternatives

In formal English, should can make a condition sound less likely or more tentative: If you should need assistance, press this button. A more formal inversion (word order with no if) is also possible: Should you need assistance, press this button. These are useful to recognise in notices and business writing, but the ordinary first conditional is more natural in everyday conversation.

Practice Tips

1. Build two-part plans. Choose five realistic conditions for tomorrow and complete them aloud: If I finish work early, ... Use will, might, can, or should according to the meaning.
2. Switch the clause order. Rewrite each sentence both ways and check the comma: If the shop is open, I'll go in → I'll go in if the shop is open.
3. Compare the connectors. Take one event and write versions with if, unless, and when. Explain how each choice changes the speaker's expectation or the negative condition.

Related Concepts

• Prerequisite: Future with Will — review how will forms predictions, decisions, promises, and negatives.
• Next step: Second Conditional — contrast real or open future possibilities with hypothetical and more remote situations.