Conditionals (zero, first, second, third)
For example:✅ If you heat ice, it melts.
We can use conditional sentences to talk about:
- facts (like in the example above),
- events that are likely,
- events that are unlikely,
- what we would change in the past.
Each one of these is a different type of conditional that has its own grammar structure. Have a look at the table below for a summary of when we use them. After, we’ll look at each type in more detail, including how to form them.
| Zero conditional | To talk about facts (where one event depends on another). | If water is hot enough, it boils. |
| First conditional | To talk about things that are likely to happen, or at least possible (not general facts). | If I don’t get enough sleep, I will be very tired. |
| Second conditional | Used for imagined situations that are unlikely to happen or that are impossible. | If I had a bigger garden, I would grow vegetables. |
| Third conditional | When thinking about what might’ve happened if the situation was different (we can’t change it). | If Jamila hadn’t been so sleepy, she wouldn’t have spilt her coffee! |
Important note: The order of the clauses (parts of the sentence) doesn’t matter. So, we can say:
✅If I don’t eat, I get hungry. (Please notice that this sentence has a comma.)
✅I get hungry if I don’t eat.
Zero conditional
We use the zero conditional to talk about facts where one event depends on another. These facts are usually things that happen in general, not specific situations.
✅ If water is hot enough, it boils.
Because these facts are always true, we can replace if with when, without changing the meaning of the sentence very much.
How to make zero conditional sentences
If + simple present, …simple present
✅ If Alan doesn’t have money, he can’t pay your bills.
✅ The alarm makes a noise if an intruder enters.
First conditional
The first conditional tells us about things that are likely to happen, or at least possible. We usually use this to talk about specific situations in the future, not general facts (that’s when we use the zero conditional).
✅ If I don’t get enough sleep, I will be very tired tomorrow.
These sentences might be predictions, advice, warnings, promises, or more. We can usually replace if with words like when, as soon as, and unless, without changing the meaning very much.
How to make first conditional sentences
if + present simple, … will/won’t + bare infinitive
✅ If I’m late, I’ll buy another train ticket.
✅ Jenny will go inside if it rains.
Second conditional
We use the second conditional for imagined situations that are unlikely to happen or that are impossible.
✅ If I won the lottery, I would move to Canada.
The main difference between the first and second conditionals is how likely the event is to happen. The first conditional includes will, a future word, to show the situation is likely. The second conditional includes would to show that it is unlikely.
How to make second conditional sentences
if + past simple, … would/wouldn’t + bare infinitive
✅ If I had a bigger garden, I would grow vegetables.
✅ She wouldn’t be so sad if she had a better job.
Important note: when we use ‘to be’ in second conditional sentences, ‘was’ becomes ‘were’. This is called the subjunctive mood. You can learn more about the subjunctive here, but don’t worry, many native speakers don’t know why we use it, just that we do!
✅ If I were you, I would take the day off!
Third conditional
We use the third conditional to imagine a different result for an event that we can’t change now (usually in the past). We’re thinking about what might’ve happened if the situation was different.
Context – My friend Jamila didn’t sleep well last night. She bought a coffee at breakfast, but she knocked it over. I can say:
✅If Jamila hadn’t been so sleepy, she wouldn’t have spilt her coffee!
In the example above, it’s clear that Jamila was sleepy and that she did spill the coffee. I can’t change that, I’m just imagining the situation was different.
For this reason, we often use the third conditional to talk about regret.
How to make third conditional sentences
if + past perfect, …would(n’t) + have + past participle
You may also see could or might instead of would.
Don’t worry if it sounds complicated. Have a look at the example sentences below and see how the parts of the sentences work together:
✅ If I hadn’t eaten ten pizzas, I would’ve ordered ice cream!
✅ If she’d checked the time, she wouldn’t have been late!
✅ Jack would’ve saved more money if he had had a better job.
A word about mixed conditionals
Sometimes, we mix the conditionals in one sentence. Here is an example of when we might do this:
- To talk about the present results of an imagined past event.
Here, we mix the ‘if clause’ of the third conditional (past perfect) with the ‘main clause’ of the second conditional (would + infinitive).
✅ If I hadn’t given my plants so much water, they would be alive now!
✅ If Tina had seen the movie, she would know it was rubbish.