English Conditionals (If-Sentences)

What is a conditional sentence?

A conditional sentence has two parts: the if-clause (the condition) and the result clause (what happens if the condition is true).

• If it rains, we will stay home.

The two clauses can come in either order, with the same meaning:

• If it rains, we will stay home.
• We will stay home if it rains.

The type of conditional depends on how real or imaginary the condition is. The verb forms in both clauses change with the type — that is what this page teaches.

Zero conditional — always true

Used for facts, scientific truths, and things that always happen when the condition is met. Here if means almost the same as when.

Form: If + simple present, ... simple present.

• If you heat ice, it melts. (scientific fact)
• If I drink coffee at night, I do not sleep well. (always true for me)
• If the light turns red, cars stop. (rule)
• Plants die if they get no water.

First conditional — real future

Used for real possibilities in the future — things that can genuinely happen, and their likely results.

Form: If + simple present, ... will + base verb.

• If it rains tomorrow, we will cancel the picnic.
• If you study tonight, you will pass the test.
• She will be angry if you arrive late.
• If we hurry, we will catch the train.

The result clause does not have to use will — it can use another modal or even a command:

• If you finish early, you can go home. (permission)
• If he calls, it might be important. (possibility)
• If you see Anna, say hello for me. (command / request)

👉 Practice: Will vs Would Quiz — pick the right result-clause form.

Second conditional — unreal present or future

Used for imaginary, unlikely, or impossible situations now or in the future — dreams, hypotheticals, and advice. The past tense here does NOT mean past time; it signals that the situation is unreal.

Form: If + simple past, ... would + base verb.

• If I had a million dollars, I would travel the world. (I do not have it)
• If she lived closer, we would meet more often. (she lives far away)
• If people could fly, airports would be empty. (impossible)
• What would you do if you won the lottery?

First or second? Both can talk about the future — the difference is how real the speaker thinks the condition is:

• If I win the race, I will celebrate. (first — a real chance; I am in the race)
• If I won the lottery, I would buy a house. (second — just a dream)

Third conditional — unreal past

Used to imagine a different past — things that did NOT happen, and their imaginary results. This is the tense of regrets and "what if" thinking about the past.

Form: If + past perfect, ... would have + past participle.

• If she had studied, she would have passed the exam. (she did not study, and she failed)
• If we had left earlier, we would have caught the train.
• I would have called you if I had known about the party.
• If he had not missed the bus, he would have arrived on time.

The result can also use could have or might have:

• If you had asked me, I could have helped.
• If the weather had been better, we might have gone hiking.

Mixed conditionals

Real life mixes time frames, and so do conditionals. The two common mixes:

Past condition → present result

Form: If + past perfect, ... would + base verb.

• If I had taken that job, I would be rich now. (past decision, present result)
• If she had caught the flight, she would be here today.

Present condition → past result

Form: If + simple past, ... would have + past participle.

• If he were more careful, he would not have broken his phone. (a general trait explains a past event)
• If I spoke French, I would have applied for that job in Paris.

Unless and other condition words

Unless means if ... not. Because unless already contains the negative, do not add another not to the same clause.

• Unless you hurry, you will miss the bus. (= If you do not hurry...)
• I will not go unless you come with me.

Other words that introduce conditions, all followed by a present tense for future meaning:

• as long as — You can borrow my car as long as you drive carefully.
• provided (that) — We will finish on time provided that everyone helps.
• when — for things that are certain, not just possible: When the movie ends, we will get dinner. (the movie will definitely end)

Common ESL mistakes

The conditional mistakes learners make most often. Click any box to hear it.

1. will inside the if-clause

2. would inside the if-clause

3. would have inside the if-clause (unreal past)

4. Mixing up second and third conditionals

Second = imaginary now / future. Third = imaginary past.

• If I knew the answer, I would tell you. (now — I do not know it)
• If I had known the answer, I would have told you. (past — I did not know it then)

5. Double negative with unless

👉 Practice: Conditional Mistakes Quiz — spot correct and incorrect if-sentences.

All types at a glance

👉 Practice: Identify the Type Quiz · Will vs Would Quiz · Common Mistakes Quiz