Updated: June 2026

Grammar Level: B1–C1 By LexFizz Team

English Conditionals: The Complete Guide (0–3 + Mixed)

Master all five types of English conditionals with clear rules and examples. Zero, first, second, third, and mixed conditionals explained for ESL learners.

Part of the Grammar Series

This article is part of our Complete English Grammar Practice Guide — explore all grammar topics with interactive exercises.

✔ Key Takeaways

There are five conditional types in English: zero, first, second, third, and mixed.
The tense combination in each conditional signals how real, probable, or hypothetical the situation is.
Never use will or would directly after if in standard conditional sentences.
Mixed conditionals combine time frames — typically a past condition with a present result, or vice versa.
Alternatives such as unless, provided that, and as long as add variety and nuance to conditional writing.

What Is a Conditional Sentence?

A conditional sentence expresses a relationship between two events or states: a condition and a result. The condition is usually introduced by if (or an equivalent word), and the result follows in the main clause. English uses different tense combinations to show how real or hypothetical the situation is.

Every conditional has two parts: the if-clause (subordinate clause) and the main clause (result clause). Either clause can come first. When the if-clause comes first, it is separated by a comma. When the main clause comes first, no comma is needed.

If it rains, I will stay at home. → if-clause first, comma required

I will stay at home if it rains. → main clause first, no comma needed

Zero Conditional — General Truths and Facts

The zero conditional describes situations that are always or generally true: scientific facts, natural laws, habits, and cause-and-effect relationships where the result is certain.

Structure: If / When + present simple → present simple

If you heat water to 100°C, it boils.

When children are tired, they become irritable.

Plants die if they don’t get enough water.

Notice that if and when are often interchangeable in zero conditionals, because the outcome is certain whenever the condition is met. The zero conditional is also used for instructions: If the alarm sounds, leave the building immediately.

First Conditional — Real and Probable Future

The first conditional talks about realistic or possible situations in the future — things that could genuinely happen. The speaker considers the situation likely or at least plausible.

Structure: If + present simple → will + base verb

If it rains tomorrow, we will cancel the picnic.

If you study hard, you will pass the exam.

She will be disappointed if he doesn’t come.

You can also use can, may, might, or should in the main clause instead of will to express varying degrees of certainty: If you ask him nicely, he might help you.

Common mistake: Do not use will in the if-clause.
✗ If it will rain, we will cancel.
✓ If it rains, we will cancel.

Second Conditional — Hypothetical Present and Future

The second conditional describes imaginary, unlikely, or impossible present or future situations. The speaker is not talking about reality — they are speculating about a different state of affairs. It is also the standard structure for giving advice with If I were you…

Structure: If + past simple → would + base verb

If I won the lottery, I would travel the world.

If she lived closer, we would see each other more often.

If I were you, I would apologise immediately.

Using the past simple in the if-clause does not mean the situation is in the past; it creates a psychological distance from reality. Compare: If I have time (first conditional — realistic) versus If I had time (second conditional — hypothetical).

Note on ‘were’: In formal writing and examinations, use were for all persons: If he were taller… / If she were here… In informal spoken English, was is widely accepted, but were is the preferred form in IELTS and academic contexts.

Third Conditional — Impossible Past

The third conditional refers to past situations that did not happen and cannot be changed. It is used to express regret, criticism, or to speculate about how a different past action would have produced a different outcome.

Structure: If + past perfect → would have + past participle

If she had applied earlier, she would have got the job.

If I had known, I would have told you.

We would have arrived on time if we had left earlier.

Contractions are common in spoken English: If she’d applied earlier, she’d have got the job. Note that British English uses got rather than gotten as the past participle of get.

Critical mistake: Never use would have in the if-clause.
✗ If I would have known, I would have helped.
✓ If I had known, I would have helped.

Mixed Conditionals — Combining Time Frames

Mixed conditionals occur when the condition and the result refer to different time frames. There are two common patterns.

Type A: Past condition → Present result

This is the most common mixed conditional. A past action (or lack of it) has consequences that are still felt in the present.

Structure: If + past perfect → would + base verb

If I had taken that job, I would be living in New York now.

If she had studied medicine, she would be a doctor today.

Type B: Present state → Past result

A permanent present characteristic or state is used to explain a past consequence.

Structure: If + past simple → would have + past participle

If he were more careful, he would not have made that mistake.

If I were a morning person, I would have caught the early train.

Quick Reference: All Five Conditionals

Type	If-clause	Main clause	Use
Zero	present simple	present simple	General truths, facts, habits
First	present simple	will + base verb	Real or probable future
Second	past simple	would + base verb	Imaginary present or future
Third	past perfect	would have + past participle	Impossible past; regret
Mixed (A)	past perfect	would + base verb	Past cause → present result
Mixed (B)	past simple	would have + past participle	Present state → past result

Alternatives to ‘If’

Varying your conditional language beyond if is important for academic writing and IELTS Band 7+ scores. The following connectors each add a slightly different nuance.

Unless (= if…not): Unless you leave now, you will miss the bus.
Provided that / Providing (strict condition): You may borrow my laptop provided that you return it by Friday.
As long as (on condition that): As long as you practise regularly, you will improve your English.
Suppose / Supposing (what if?): Supposing you won a million pounds, what would you do first?
Even if (the result stays the same): Even if it rains, we will go to the match.
In case (precautionary action): Take an umbrella in case it rains.

Conditionals in Formal Writing and IELTS

Conditionals are essential for discussing causes, consequences, and recommendations in IELTS Writing Task 2 and academic essays. Showing command of multiple conditional types demonstrates grammatical range, which examiners reward with higher band scores.

First conditional: If governments invest in renewable energy, carbon emissions will fall significantly.
Second conditional: If more people used public transport, air quality in cities would improve considerably.
Third conditional: If stricter regulations had been introduced earlier, the environmental damage would not have reached this level.

In formal academic writing, inverted conditionals (without if) are also used to add sophistication: Had the government acted sooner, the crisis could have been averted. / Were the policy to change, thousands of jobs would be at risk.

Common Mistakes to Avoid

Even B2–C1 learners make the following errors with conditionals. Being aware of them will help you avoid them in both writing and speech.

Using will in the if-clause: ✗ If it will be sunny… ✓ If it is sunny…
Using would have in the if-clause of the third conditional: ✗ If I would have seen her… ✓ If I had seen her…
Confusing second and third conditionals: Using would have when referring to a present hypothetical instead of past impossible.
Forgetting the comma when the if-clause comes first in written English.
Using was instead of were in formal or exam writing for the second conditional if-clause.

Practise Your Conditionals

Reading about grammar rules is only the first step. To truly internalise conditional sentences, you need regular interactive practice. LexFizz offers free exercises designed specifically for ESL and EFL learners at B1–C1 level.

Grammar Quiz — multiple-choice questions on all conditional types.
Complete the Sentence — choose the correct conditional verb form.
Cloze Dropdown — fill gaps using the right conditional tense.
Unjumble — reorder words to form grammatically correct conditional sentences.

Ready to practise conditionals?

Explore All Grammar Exercises →

Frequently Asked Questions

What are the five types of conditional sentences in English?

English has five main conditional types: Zero Conditional (If water reaches 100°C, it boils — general truths); First Conditional (If it rains, I will stay home — realistic future); Second Conditional (If I won the lottery, I would travel — hypothetical present or future); Third Conditional (If I had studied harder, I would have passed — impossible past); Mixed Conditional (If I had taken that job, I would be rich now — past cause, present result). Each type uses a different combination of tenses to signal how real or hypothetical the situation is.

What is the difference between the first and second conditional?

The first conditional describes a realistic or probable future scenario: If I finish early, I will call you. The second conditional describes an imaginary, unlikely, or impossible present or future situation: If I were a millionaire, I would buy a yacht. The key difference is probability — first conditional events could genuinely happen, while second conditional events are hypothetical. The first conditional uses present simple in the if-clause; the second uses past simple.

Why do we use the past simple in the second conditional if we are talking about the present or future?

Using the past simple in the if-clause of a second conditional does not mean the situation is in the past. Instead, the past tense creates psychological distance from reality, signalling to the listener that the situation is imaginary or hypothetical. This is called backshift. Compare: If I have time (first conditional — realistic possibility) with If I had time (second conditional — I do not actually have time right now).

How do I use the third conditional in English?

The third conditional (If + past perfect, would have + past participle) refers to imaginary past situations — things that did not happen and cannot be changed: If she had applied earlier, she would have got the job. It expresses regret, criticism, or speculation about a different past outcome. A critical and very common mistake is using ‘would have’ in the if-clause: say ‘If I had known’ NOT ‘If I would have known’.

Can I use ‘were’ instead of ‘was’ in the second conditional?

Yes, and it is strongly recommended in formal writing and examinations. In standard grammar, ‘were’ is used for all persons in the second conditional if-clause: If I were you, I would apologise. If he were taller, he could reach the shelf. Using ‘was’ (If I was you) is common in informal spoken English but ‘were’ is preferred for IELTS, Cambridge exams, and academic writing. The fixed expression ‘If I were you’ always uses ‘were’.

What are mixed conditionals and how do I use them?

Mixed conditionals combine elements from different conditional types to describe situations across two time frames. The most common type (Type A) describes a past cause with a present result: If I had taken that job (past perfect), I would be living in New York now (would + base verb). Type B describes a present state with a past consequence: If she were more careful (past simple), she would not have made that mistake (would have + past participle).

What is the zero conditional used for?

The zero conditional (If / When + present simple, present simple) expresses general truths, scientific facts, habits, and cause-and-effect relationships that are always true: If you heat ice, it melts. When people are stressed, they sometimes make poor decisions. The word ‘when’ is often interchangeable with ‘if’ in zero conditionals because the outcome is certain whenever the condition is met. It is also used for instructions: If the alarm sounds, leave the building immediately.

What tense comes after ‘if’ in each conditional type?

Zero: present simple. First: present simple (never ‘will’). Second: past simple (or ‘were’ for all persons). Third: past perfect. Mixed (Type A): past perfect in the if-clause. Mixed (Type B): past simple in the if-clause. The golden rule is that ‘will’ and ‘would’ should not appear directly after ‘if’ in standard conditional sentences. Use a tense form instead.

Are there alternatives to ‘if’ in conditional sentences?

Yes. ‘Unless’ means ‘if not’: Unless you hurry, you will miss the bus. ‘Provided that / providing’ adds a stricter condition: You can borrow the car provided that you fill the tank. ‘As long as’ means on condition that: As long as you practise, you will improve. ‘Suppose / supposing’ means ‘what if’: Supposing you won, what would you do? ‘Even if’ shows the result is unchanged: Even if it rains, we will go. Each alternative adds a slightly different nuance or degree of formality.

How do conditionals help in IELTS Writing Task 2?

Conditionals are essential for discussing causes, consequences, and recommendations in academic writing. Using multiple conditional types accurately demonstrates grammatical range, which examiners reward. For example: First conditional — If governments invest in renewable energy, carbon emissions will fall. Second conditional — If more people used public transport, air quality would improve considerably. Third conditional — If stricter laws had been introduced earlier, the crisis would not have reached this point. Inverted conditionals (Had the policy changed…) are also impressive at Band 7+ level.