English Conditionals: The Complete Guide

This article provides a comprehensive, all-in-one guide to English conditionals (Zero, First, Second, Third, and Mixed), designed for intermediate learners at levels B1 to B2 who want to express possibilities, hypotheses, and consequences with precision and confidence.

The essential idea you must understand is that conditionals are "if-then" statements that express cause and effect, possibilities, hypothetical situations, and regrets. Each conditional has a specific structure and meaning — from general truths to impossible past regrets.

You will discover why the incorrect If I will see her, I will tell her. becomes the correct If I see her, I will tell her., and how mastering all five conditionals can dramatically improve your English fluency.

The key question to keep in mind is: How likely is this situation — real, possible, unlikely, or impossible?

The main rule to remember is: In conditional sentences, the "if" clause contains the condition, and the main clause contains the result. The verb tenses depend on how likely the condition is.

By the end of this lesson, you will be able to use all five conditionals correctly to express everything from scientific facts to dreams and regrets.

What Are Conditionals?

The Five English Conditionals at a Glance

Conditionals are sentences that express cause and effect — they say that something will happen if something else happens. They always have two parts: the "if" clause (condition) and the main clause (result).

TypeUseStructureExample
ZeroGeneral truths / FactsIf + present, presentIf you heat ice, it melts.
FirstReal / Possible futureIf + present, will + infinitiveIf it rains, I will stay home.
SecondUnreal / Unlikely present/futureIf + past, would + infinitiveIf I won the lottery, I would travel.
ThirdUnreal past (regrets)If + past perfect, would have + past participleIf I had studied, I would have passed.
MixedUnreal past with present resultIf + past perfect, would + infinitiveIf I had studied, I would be a doctor now.
💡 Important: Conditionals are sometimes called "if-clauses" because they almost always begin with the word "if". However, the "if" clause can also come after the main clause.

The Key Question: How Likely Is This Situation?

To choose the correct conditional, ask yourself:

"How likely is this situation — real/true, possible, unlikely, or impossible?"

📊 Zero

100% True / Always

"If you heat water, it boils."

✅ First

50-90% Possible

"If it rains, I'll stay home."

❓ Second

10-30% Unlikely

"If I won, I'd travel."

❌ Third

0% Impossible (past)

"If I had studied, I'd have passed."

🔄 Mixed

Past → Present

"If I had studied, I'd be a doctor."

The Golden Rule: Verb Tenses in Conditionals

⚡ The verb tense in the "if" clause determines the conditional type — and the main clause follows a specific pattern!
💡 Remember: The "if" clause never uses will, would, or would have — these belong in the main clause only.

The Complete Rules of Conditionals

Zero Conditional — General Truths & Scientific Facts

The Zero Conditional expresses things that are always true — scientific facts, general truths, and habits. The result is always 100% certain.

📊 Zero Conditional

Structure: If + present simple, present simple

  • If you heat water, it boils.
  • If I am late, my boss gets angry.
  • If you don't eat, you get hungry.

💡 Usage

  • Facts: If you freeze water, it becomes ice.
  • Habits: If I drink coffee late, I don't sleep.
  • Instructions: If the light is red, you stop.
💡 Tip: You can replace "if" with "when" in zero conditionals because the result is always true. "When you heat water, it boils." = "If you heat water, it boils."

First Conditional — Real & Possible Future Situations

The First Conditional expresses real and possible situations in the future. There is a real chance that the condition will happen.

✅ First Conditional

Structure: If + present simple, will + base verb

  • If it rains, I will stay home.
  • If she studies, she will pass the exam.
  • If we leave now, we will catch the train.

💡 Usage

  • Plans: If I finish work early, I'll go to the gym.
  • Warnings: If you don't study, you'll fail.
  • Promises: If you help me, I'll help you.

⚠️ Important: The "if" clause never uses "will" — it uses present simple.

❌ If I will see her, I will tell her. → ✅ If I see her, I will tell her.

Second Conditional — Unlikely or Hypothetical Situations

The Second Conditional expresses unlikely, hypothetical, or imaginary situations in the present or future. The condition is not real or very unlikely.

❓ Second Conditional

Structure: If + past simple, would + base verb

  • If I won the lottery, I would travel the world.
  • If she spoke Spanish, she would get the job.
  • If we had more time, we would visit you.

💡 Usage

  • Dreams: If I were rich, I'd buy a house.
  • Advice: If I were you, I'd accept the offer.
  • Imaginary: If I could fly, I'd travel everywhere.
💡 Important: In the second conditional, we often use "were" instead of "was" with all subjects (including I, he, she, it) in formal English.
✅ If I were you... (formal) / If I was you... (informal)

Third Conditional — Impossible Past (Regrets & Missed Opportunities)

The Third Conditional expresses impossible situations in the past. We use it to talk about regrets, missed opportunities, and things that didn't happen.

❌ Third Conditional

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

  • If I had studied, I would have passed the exam.
  • If she had taken the job, she would have moved to London.
  • If we had left earlier, we would have arrived on time.

💡 Usage

  • Regrets: If I had known, I would have helped.
  • Missed chances: If she had applied, she would have gotten it.
  • Criticism: If you had listened, you'd have understood.
💡 Remember: The third conditional always talks about the past — and the situation is impossible to change now.

Mixed Conditional — Past Condition with Present Result

The Mixed Conditional connects the past with the present. It talks about a past action that affects the present situation. The condition is in the past, but the result is in the present.

🔄 Mixed Conditional

Structure: If + past perfect, would + base verb

  • If I had studied medicine, I would be a doctor now.
  • If she had taken that job, she would live in Paris.
  • If they had invested wisely, they would be rich today.

💡 Usage

  • Past action, present result: If I had studied, I would have a better job now.
  • Missed opportunity: If she had said yes, they would be married now.
💡 Key Difference: The third conditional talks about how the past could have been different. The mixed conditional talks about how the past affects the present.

Examples with Deep Explanation

Example 1: Zero Conditional — Scientific Fact

If you heat water to 100°C, it boils.

Meaning: This is a scientific fact. Every time you heat water to 100°C, it boils. The result is 100% certain.

Why it works: Both clauses use the present simple tense. This shows that the condition and result are always true.

Key question: How likely is this situation? → 100% true / Always → So we use the Zero Conditional.

Example 2: First Conditional — Real Future Possibility

If it rains tomorrow, I will stay at home.

Meaning: There is a real chance that it will rain tomorrow. If it does, I will stay home.

Why it works: The "if" clause uses the present simple ("rains"), and the main clause uses will + base verb ("will stay"). This shows a real, possible future situation.

Key question: How likely is this situation? → 50-90% possible → So we use the First Conditional.

⚠️ Remember: The "if" clause never uses "will" — it uses present simple.

Example 3: Second Conditional — Unlikely Dream

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

Meaning: Winning the lottery is very unlikely, but I am imagining what I would do if it happened.

Why it works: The "if" clause uses the past simple ("won"), and the main clause uses would + base verb ("would travel"). This shows an unlikely or imaginary situation.

Key question: How likely is this situation? → 10-30% unlikely → So we use the Second Conditional.

💡 Tip: In this type, we often say "If I were rich" instead of "If I was rich" — especially in formal English.

Example 4: Second Conditional — Hypothetical Advice

If I were you, I would accept the offer.

Meaning: I am not you, so this is a hypothetical situation. I am giving you advice based on what I would do if I were in your position.

Why it works: This uses the second conditional structure. "Were" is used with all subjects in this fixed expression.

💡 Important: "If I were you" is a fixed expression — you cannot say "If I was you" in formal contexts.

Example 5: Third Conditional — Past Regret

If I had studied harder, I would have passed the exam.

Meaning: I didn't study hard in the past, and I failed the exam. Now I regret it, but I cannot change it.

Why it works: The "if" clause uses the past perfect ("had studied"), and the main clause uses would have + past participle ("would have passed"). This shows an impossible past situation.

Key question: How likely is this situation? → 0% impossible (past) → So we use the Third Conditional.

💡 Remember: The third conditional is often used to express regret about the past.

Example 6: Mixed Conditional — Past Action, Present Result

If I had studied medicine, I would be a doctor now.

Meaning: I didn't study medicine in the past, so I am not a doctor now. The past action affects the present situation.

Why it works: The "if" clause uses the past perfect ("had studied") — condition in the past. The main clause uses would + base verb ("would be") — result in the present.

Key question: How likely is this situation? → Past condition, present result → So we use the Mixed Conditional.

💡 Key Difference: Third conditional = past + past. Mixed conditional = past + present.

Example 7: Zero Conditional — Habit

If I drink coffee late at night, I don't sleep well.

Meaning: This is a general truth about my habit. Every time I drink coffee late, the result is the same.

Why it works: Both clauses use the present simple tense. This shows a general truth or habit.

Example 8: First Conditional — Warning

If you don't wear a helmet, you will get a fine.

Meaning: There is a real possibility that you won't wear a helmet. If that happens, you will get a fine.

Why it works: The "if" clause uses the present simple ("don't wear"), and the main clause uses will + base verb ("will get"). This is a clear warning about a possible future consequence.

Common Mistakes & Logical Corrections

Mistake 1: Using "Will" in the "If" Clause

If I will see her, I will tell her.
If I see her, I will tell her.

Why Does It Change?

In conditional sentences, the "if" clause never uses "will". Use the present simple in the "if" clause for the first conditional.

❌ If I will see → ✅ If I see

Remember: Only the main clause can use "will."

Mistake 2: Using "Would" in the "If" Clause

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

Why Does It Change?

In the second conditional, the "if" clause uses the past simple, not "would." "Would" is for the main clause only.

❌ If I would win → ✅ If I won

Remember: The "if" clause never uses "would" — only the main clause does.

Mistake 3: Confusing First and Second Conditionals

If I had money, I will buy a car.
If I have money, I will buy a car. (First — real possibility)
If I had money, I would buy a car. (Second — unlikely)

Why Does It Change?

The verb tense in the "if" clause determines the conditional type and the main clause verb.

If I have → will buy (First — possible)
If I had → would buy (Second — unlikely)

Remember: Choose the conditional based on how likely the situation is.

Mistake 4: Confusing Third and Mixed Conditionals

If I had studied, I would be a doctor now.
If I had studied, I would have been a doctor. (Third — past result)
If I had studied, I would be a doctor now. (Mixed — present result — correct!)

Why Does It Change?

Both sentences are correct — they have different meanings. The third conditional talks about a past result. The mixed conditional talks about a present result of a past action.

Third: past + past → "I would have been a doctor." (I'm not a doctor now)
Mixed: past + present → "I would be a doctor now." (I'm not a doctor now because I didn't study)

Remember: Use the third conditional for past results. Use the mixed conditional for present results of past actions.

Mistake 5: Using "Was" Instead of "Were" in Formal Second Conditional

If I was rich, I would buy a house. (informal)
If I were rich, I would buy a house. (formal)

Why Does It Change?

In formal English, we use "were" with all subjects (I, he, she, it) in the second conditional. In informal English, "was" is sometimes used.

✅ If I were you... (formal) / ✅ If I was you... (informal)

Remember: "If I were you" is a fixed expression — always use "were."

Practice Exercises

Task 1: Choose the Correct Conditional

Choose the correct conditional type (Zero, First, Second, Third, or Mixed) for each sentence:

  • 1. If you heat ice, it melts. → ______
  • 2. If I win the lottery, I'll buy a house. → ______
  • 3. If I were you, I'd accept the job. → ______
  • 4. If she had studied, she would have passed. → ______
  • 5. If I had studied, I would be a doctor now. → ______

Task 2: Complete the Conditional Sentences

Fill in the blanks with the correct verb forms:

  • 1. If it ______ (rain) tomorrow, I ______ (stay) home.
  • 2. If I ______ (have) more time, I ______ (travel) more.
  • 3. If she ______ (study) harder, she ______ (pass) the exam.
  • 4. If you ______ (heat) water to 100°C, it ______ (boil).
  • 5. If I ______ (know) the answer, I ______ (tell) you.

Task 3: Write Sentences Using All Conditionals

Write one sentence for each conditional type:

  • 1. Zero: A scientific fact
  • 2. First: A real future possibility
  • 3. Second: An unlikely dream
  • 4. Third: A past regret
  • 5. Mixed: A past action with present result

Task 4: Conditional Story

Write a short paragraph (5-7 sentences) about a decision you made in the past and how it affects your present life. Use at least three different conditionals.

Example: "If I had studied engineering, I would have a better job now. But if I had chosen that path, I wouldn't have met my best friends. If I could go back, I would make the same choice again."

Quick Quiz

Quiz 1: The Key Question

What is the key question you should ask yourself when choosing a conditional?

Answer

"How likely is this situation — real/true, possible, unlikely, or impossible?"

Quiz 2: Choose the Correct Conditional

What type of conditional is this sentence? "If I had known, I would have helped."

Answer

Third Conditional — impossible past

Why? The "if" clause uses past perfect ("had known"), and the main clause uses "would have + past participle" ("would have helped"). This talks about an impossible past situation.

Quiz 3: The Golden Rule

What is the golden rule about the "if" clause and "will" / "would"?

Answer

The "if" clause never uses "will" or "would" — it uses present simple, past simple, or past perfect. "Will" and "would" belong in the main clause only.

Quiz 4: Find the Mistake

What is wrong with: "If I would win the lottery, I would travel."

Answer

If I won the lottery, I would travel.

Why? The "if" clause in the second conditional uses the past simple ("won"), not "would win." "Would" belongs only in the main clause.

Quiz 5: Write Your Own Sentence

Write a sentence using the mixed conditional (past condition, present result).

Model Answer

"If I had studied harder, I would have a better job now."

Analysis: Past condition ("had studied") + present result ("would have"). This is the mixed conditional.

Final Review: Master Conditionals

To complete your journey with English conditionals, review these key points and use this checklist to ensure you've mastered everything.

📊 Zero

100% True

"If you heat ice, it melts."

✅ First

Possible future

"If it rains, I'll stay."

❓ Second

Unlikely present

"If I won, I'd travel."

❌ Third

Impossible past

"If I had studied, I'd have passed."

🔄 Mixed

Past → Present

"If I had studied, I'd be a doctor."

  • Ask the key question: How likely is this situation — real/true, possible, unlikely, or impossible?

    Zero → 100% true / First → 50-90% possible / Second → 10-30% unlikely
    Third → 0% impossible (past) / Mixed → Past condition, present result

  • Remember the golden rule: The "if" clause never uses "will" or "would" — only the main clause does.

    ✅ If I see her, I will tell her. 
    ❌ If I will see her, I will tell her.

  • Match the tenses correctly: Each conditional has a specific structure. Learn the patterns and practice them.

    Zero: If + present, present
    First: If + present, will + infinitive
    Second: If + past, would + infinitive
    Third: If + past perfect, would have + past participle
    Mixed: If + past perfect, would + infinitive

  • Compare your sentences with correct models: Before finishing, compare your sentences with the examples in this article to catch any errors.

    Compare → Correct → Confirm

📌 Quick Summary: Conditionals

📊 Zero

Facts / Truths
"If you heat ice, it melts."

✅ First

Real future
"If it rains, I will stay."

❓ Second

Unlikely present
"If I won, I would travel."

❌ Third

Impossible past
"If I had studied, I would have passed."

🔄 Mixed

Past → Present
"If I had studied, I would be a doctor."

🔑 Remember: Choose your conditional based on how likely the situation is. The "if" clause never uses "will" or "would" — only the main clause does. What's your situation — real, possible, unlikely, or impossible?

🎯 Next Step: Write a short paragraph about a past decision and its present result using at least 3 different conditionals.

Remember: "How likely is this situation — real/true, possible, unlikely, or impossible?"

Phrasal Verbs: All-in-One tabs

Complete verb learning center

Phrasal Verbs & Other Verbs

Browse, compare, learn usage, and practice with randomized quizzes from one learning card.

7 learning sections
Choose a section above The learning content stays closed until you are ready.
Learning center is open Switch tabs at any time.
Learn combinations in context

Phrasal Verbs Library

Sort by level, base verb, primary particle, structure, meaning group, or teaching priority.

20of 359 shown

close down

close+down
Common

stop operating a business, organization, or facility

Example

The store will close down at the end of the year.

Grammar & classification
Two Word Separable Both Particle: down Cease Business

chip in

chip+in
Extended

contribute money, effort, or ideas with other people

Example

Everyone can chip in a few dollars.

Grammar & classification
Two Word Inseparable Intransitive Particle: in Contribute

look back on

look+back+on
Ultra Core

think about or remember something from the past

Example

I often look back on my first year here.

Grammar & classification
Three Word Inseparable Transitive Particle: back Remember Past

give up

give+up
Ultra Core

stop doing or using something, especially a habit

Example

He is trying to give up smoking.

Grammar & classification
Two Word Separable Transitive Particle: up Stop Habit

break into

break+into
Ultra Core

enter a building or place illegally or by force

Example

Someone tried to break into the store last night.

Grammar & classification
Two Word Inseparable Transitive Particle: into Enter Illegally

mess up

mess+up
Extended

damage, spoil, or make a serious mistake with something

Example

I do not want to mess up this opportunity.

Grammar & classification
Two Word Separable Transitive Particle: up Ruin Mistake

pop in

pop+in
Extended

enter or leave a place briefly and informally

Example

I may pop in after lunch.

Grammar & classification
Two Word Inseparable Intransitive Particle: in Visit Brief

run away

run+away
Ultra Core

escape from a place, person, or difficult situation

Example

They managed to run away before anyone noticed.

Grammar & classification
Two Word Inseparable Intransitive Particle: away Escape

lock up

lock+up
Common

lock all doors or secure a place before leaving

Example

Please lock up before you leave.

Grammar & classification
Two Word Separable Both Particle: up Lock Secure

barge in

barge+in
Extended

enter or interrupt suddenly and rudely

Example

He barged in while we were discussing the budget.

Grammar & classification
Two Word Inseparable Intransitive Particle: in Interrupt

break down

break+down
Ultra Core

stop working because of a mechanical or system failure

Example

The car may break down if we ignore that noise.

Grammar & classification
Two Word Inseparable Intransitive Particle: down Machine Fail

Sense: machine or system failure.

live through

live+through
Common

experience or endure a difficult process or period

Example

She had to live through a difficult year.

Grammar & classification
Two Word Inseparable Transitive Particle: through Experience

get going

get+going
Ultra Core

start an activity, process, business, or event

Example

The new project is ready to get going.

Grammar & classification
Two Word Inseparable Intransitive Particle: going Start

use up

use+up
Extended

use all of a supply so that none remains

Example

We may use up the fuel before we arrive.

Grammar & classification
Two Word Separable Transitive Particle: up Use Completely

pick up

pick+up
Ultra Core

learn or acquire a skill or information informally

Example

Travelers can pick up a lot of Spanish by listening carefully.

Grammar & classification
Two Word Separable Transitive Particle: up Learn Informally

Sense: learn informally.

pick up

pick+up
Ultra Core

collect, lift, or retrieve someone or something

Example

I will pick up the package this afternoon.

Grammar & classification
Two Word Separable Transitive Particle: up Collect Pickup

drive off

drive+off
Extended

drive away from a place

Example

They drive off before I could speak to them.

Grammar & classification
Two Word Inseparable Intransitive Particle: off Drive Leave

give away

give+away
Ultra Core

give something free to another person or organization

Example

We plan to give away the old furniture.

Grammar & classification
Two Word Separable Transitive Particle: away Donate

Sense: donate.

make out

make+out
Ultra Core

understand, interpret, or recognize something

Example

I am trying to make out what this message means.

Grammar & classification
Two Word Separable Transitive Particle: out Understand

Sense: understand or discern.

catch up

catch+up
Common

reach the same level or position as someone ahead

Example

I need to catch up after missing two classes.

Grammar & classification
Two Word Inseparable Intransitive Particle: up Catch Same Level