A conditional is a sentence with two parts: an if-clause stating a condition, and a main clause stating the result. English has five common patterns — zero, first, second, third, and mixed conditionals — each showing a different relationship between the condition and reality.
What Is a Conditional?
Conditional sentences let speakers talk about cause and effect, possibility, and hypothetical situations. Every conditional has two clauses: the if-clause (the condition) and the main clause (the result). The verb tense in each clause signals how likely or real the situation is.
The zero conditional (if + present simple, present simple) states general truths and facts: "If you heat ice, it melts." The first conditional (if + present simple, will + base verb) describes real, likely future possibilities: "If it rains, I will take an umbrella." The second conditional (if + past simple, would + base verb) describes unreal or unlikely present/future situations: "If I won the lottery, I would travel the world." The third conditional (if + past perfect, would have + past participle) describes an impossible past situation and its imagined result: "If she had studied, she would have passed."
A mixed conditional combines time frames, for example a past condition with a present result ("If I had taken that job, I would be rich now"). Choosing the right conditional type depends on whether the situation is a fact, a real possibility, an unlikely idea, or something that cannot be changed because it is already in the past. Reference grammars such as the Cambridge Grammar guide document these conditional patterns in detail.
Examples
| Example | Notes |
|---|---|
| If you heat water to 100°C, it boils. | Zero conditional — general truth |
| If it rains tomorrow, we will stay home. | First conditional — real future possibility |
| If I had more time, I would learn Japanese. | Second conditional — unreal present |
| If they had left earlier, they would have caught the train. | Third conditional — unreal past |
| If I had studied medicine, I would be a doctor now. | Mixed conditional — past condition, present result |
Related Grammar Terms
Practise Conditionals
Frequently Asked Questions
What is a conditional sentence?
A conditional sentence has an if-clause expressing a condition and a main clause expressing the result, such as "If it rains, I will stay home."
What is the zero conditional used for?
The zero conditional (if + present simple, present simple) expresses general truths, facts, and things that always happen: "If you mix red and blue, you get purple."
What is the difference between the first and second conditional?
The first conditional describes real, likely future situations ("If it rains, I will take an umbrella"). The second conditional describes unreal or unlikely present/future situations ("If I won the lottery, I would travel").
How do you form the third conditional?
Form it with if + past perfect in the condition clause, and would have + past participle in the result clause: "If she had studied, she would have passed the exam." It refers to an imagined result for a past situation that did not happen.
What is a mixed conditional?
A mixed conditional combines two different time frames in one sentence, such as a past condition with a present result: "If I had taken that job, I would be rich now."
Can you use will in the if-clause?
Generally no — standard conditionals avoid "will" in the if-clause. An exception is when "will" expresses willingness or a polite request: "If you will wait here, I'll fetch the manager."
Is unless the same as if not?
Yes, "unless" usually means "if not": "Unless you hurry, you will miss the bus" means "If you don't hurry, you will miss the bus."
Can conditionals appear without the word if?
Yes. Inverted conditionals drop "if" and invert the subject and auxiliary: "Had I known, I would have called" instead of "If I had known, I would have called."
What tense follows if in the first conditional?
The if-clause in the first conditional uses the present simple, even though the meaning refers to the future: "If it rains" (not "if it will rain").
How can I practise conditionals?
Try LexFizz's conditionals exercises, which cover all five types with fill-in-the-blank, quiz, and sentence-building activities.