First Conditional

The first conditional (also called conditional type 1, if clauses type 1, 1st conditional, or the real conditional) is used to talk about real future possibilities — things that are likely or possible in the future. It is one of the most important structures in everyday English, used for predictions, promises, warnings, and plans.

Think of the first conditional as 1 Formula with 3 Expansions:

1. The Core Formula: If + present simple, will + base verb
2. Expansion 1 — More Connectors: unless, as long as, provided that, in case
3. Expansion 2 — More Result Options: may, might, can, could, should, imperatives, going to
4. Expansion 3 — Time Clauses: when, before, after, until, as soon as

Master the core formula first, then expand in each direction. By the end of this lesson, you'll be able to build first conditional sentences with confidence using all of these tools.

Don't confuse the first conditional with:

• The zero conditional (If + present simple, present simple) — used for things that are always true, not specific future possibilities. If you need to review the differences between the zero and first conditional, see Zero Conditional for details.
• The second conditional (If + past simple, would + base verb) — used for unreal or unlikely situations. If you say "If I won the lottery, I would buy a house", you don't really expect to win. The first conditional is for things you think can really happen.

The Basic Formula: If + Present Simple, Will + Base Verb

The first conditional has one core structure:

This tells us: if this real thing happens, this will be the result. You're talking about a specific future possibility — not a general truth (that's the zero conditional) and not an imaginary situation (that's the second conditional).

Affirmative Sentences

• If it rains tomorrow, we will stay at home.
• If you study hard, you will pass the exam.
• If he gets the job, he**'ll** move to New York.
• If I save enough money, I**'ll** buy a new laptop.

Contracted forms are very common in spoken English and informal writing:

Negative Forms

Either clause (or both) can be negative:

In the if-clause, use don't / doesn't + base verb (present simple negative). In the result clause, use won't (will not) + base verb.

Clause Order: If-clause First or Second

You can put the if-clause first or second — the meaning stays the same:

🚨 The "Will" Trap — The #1 First Conditional Mistake

This is the single most common mistake learners make:

❌ If it will rain tomorrow, we will stay at home. ✅ If it rains tomorrow, we will stay at home.

The rule is absolute: NEVER use "will" in the if-clause. The if-clause always uses the present simple, even though you're talking about the future. "Will" belongs only in the result clause.

Why do learners make this mistake? Because the if-clause talks about the future, it feels natural to use "will". But English uses the present simple to represent the future in conditional and time clauses. This rule applies to all conditional types, not just the first conditional.

👉 Practice First Conditional Basics →

Beyond "If": Unless, As Long As & More Connectors

The word "if" is not the only way to introduce a condition. English has several other connectors, each with a slightly different meaning. All of them follow the same rule: present simple in the condition clause, never "will".

Unless = If ... Not

Unless means "if ... not". It already contains the negative, so use an affirmative verb after it.

⚠️ Double Negative Trap:

• ❌ Unless you don't hurry, you'll be late.
• ✅ Unless you hurry, you'll be late.

Because "unless" already means "if not", adding "don't" creates a double negative that reverses the meaning. This is the second most common first conditional mistake after the "will" trap.

As Long As / Provided That / On Condition That

These connectors all mean "only if" — they set a strict requirement that must be met:

All three are interchangeable in meaning — choose based on formality.

In Case ≠ If

"In case" is often confused with "if", but they have different meanings:

More examples of "in case":

• Write down the address in case you forget it. (= write it NOW as a precaution)
• Take some snacks in case you get hungry on the way. (= take them NOW, before the journey)
• Save your work frequently in case the computer crashes. (= save NOW to prepare for a possible crash)

Connector Summary Table

👉 Practice Unless, As Long As & Other Connectors →

Modal Variations, Imperatives & "Going To"

The first conditional is not limited to "will" in the result clause. You can use other modal verbs, imperatives, and "going to" to express different meanings.

Choosing the Right Modal

Key insight: Use "will" when the result is certain. Use "may", "might", or "could" when the result is only possible. Use "should" when giving advice. Use "can" for permission or available options.

Imperatives in the Result Clause

The result clause can be a command or instruction (imperative) instead of a statement. This is very common in safety instructions, rules, and requests:

• If you see a fire, call 999 immediately.
• If the boss asks, tell him I've gone to lunch.
• If you find my keys, please bring them to reception.

Negative imperatives use don't + base verb:

• If you hear strange noises at night, don't go outside alone.
• If the alarm goes off, don't touch anything and wait for instructions.

"Going To" for Plans and Intentions

When the result is a pre-existing plan rather than a spontaneous decision, use "going to":

• If we save enough, we are going to travel to Japan next summer. (= the plan already exists)
• As soon as I find a job, I**'m going to** save for a holiday. (= the intention is already decided)

"Will" vs "going to": Both are correct in the first conditional. Use "will" for on-the-spot decisions or predictions: "If it rains, I'll take a taxi." Use "going to" for decisions already made: "If it rains, I'm going to take a taxi" (= I've already decided this).

👉 Practice Modal Variations, Imperatives & "Going To" →

Future Time Clauses: When, Before, After, Until, As Soon As

Future time clauses follow exactly the same rule as the if-clause in the first conditional: use present simple, never "will". This is because time conjunctions like "when", "before", "after", "until", and "as soon as" work the same way as "if" when referring to the future.

The Shared Rule

🚨 The same "will" trap applies here: Never use "will" after when, before, after, until, as soon as, or by the time when talking about the future.

• ❌ When she will get home, I'll tell her.
• ✅ When she gets home, I'll tell her.

When vs If: Certainty vs Possibility

In the first conditional, "when" and "if" are not interchangeable (unlike in the zero conditional):

Use "if" when the event is uncertain. Use "when" when you expect it to happen.

Mixing Time Clauses with If Clauses

In real English, first conditional sentences often combine "if" clauses with time clauses:

• If she calls, I'll tell her the news when I see her.
• When the semester ends, I**'ll** be able to relax — if I pass all my exams.
• I'll keep working until I finish this report, if the office stays open.

Time Conjunction Quick Reference

👉 Practice Future Time Clauses →

Common Mistakes to Avoid

Quick Summary

The Core Formula:

If + present simple, will + base verb — for real future possibilities.

How to Build a First Conditional Sentence (5 Steps)

1. Identify the situation: Is it a real, possible future event? → Use the first conditional. (If it's always true → zero conditional. If it's unreal/unlikely → second conditional.)
2. Write the condition clause: Use present simple — never "will". (If she comes..., Unless it rains..., As soon as he arrives...)
3. Choose the connector: if (standard) | unless (if not) | as long as / provided that (only if) | in case (precaution) | when / before / after / until / as soon as (time)
4. Write the result clause: Choose the right form — will (certain) | may/might/could (possible) | should (advice) | can (permission/ability) | imperative (command) | going to (plan)
5. Check punctuation: Comma after the condition clause if it comes first. No comma if the result clause comes first.

Connector Comparison

Modal Meanings in First Conditional

Practice Tips

1. Start with the formula: Write 10 sentences using "If + present simple, will + base verb". Focus on getting the tense right in both clauses before adding complexity.
2. Practice the "unless" conversion: Take any "if...not" sentence and rewrite it with "unless". Check: did you accidentally keep the negative?
3. Substitute modals: Take a first conditional sentence with "will" and rewrite it with "might", "could", and "should". Notice how the meaning changes each time.
4. Spot the trap in real life: When you read English online or in textbooks, look for first conditional sentences. Check whether "will" appears in the if-clause — it shouldn't!
5. Mix time clauses and if-clauses: Write a short paragraph about your weekend plans using "if", "when", "before", "after", and "as soon as". This builds fluency with the shared present simple rule.

Practice All Exercises

Ready to practise your first conditional skills? These first conditional exercises online come with answers and explanations for every question. Work through all 4 sets — from basic conditional sentences type 1 to future time clauses — for comprehensive A2 to B1 level practice:

Whether you're looking for first conditional exercises with answers, 1st conditional worksheets, first conditional exercises PDF, or if clauses type 1 exercises for ESL learners, these multiple-choice conditional sentences exercises cover everything from the basic if-clause structure to advanced modal variations and future time clauses.