Zero Conditional: Form, Uses and Examples
The zero conditional talks about things that are always true when something happens: facts, rules of science and everyday routines. It is the simplest conditional, because both parts use the present simple.
By LearnLingo Team · Updated
Form
| If clause (condition) | Main clause (result) | Full sentence |
|---|---|---|
| If + present simple | present simple | If you heat water to 100 degrees, it boils. |
| If + present simple | present simple (negative) | If plants don't get water, they die. |
| If + present simple | imperative | If you feel sick, stay at home. |
| Main clause first | no comma | Water boils if you heat it to 100 degrees. |
Put a comma after the if clause when it comes first. When the main clause comes first, there is no comma.
| Form | Example |
|---|---|
| Negative in the if clause | If you don't water plants, they die. |
| Negative in the result | If I drink coffee late, I don't sleep well. |
| Question | What happens if you mix blue and yellow? |
| Question | Do you get a discount if you pay in cash? |
| Type | Form | Meaning | Example |
|---|---|---|---|
| Zero | if + present, present | always true | If it rains, the streets get wet. |
| First | if + present, will + verb | a real future possibility | If it rains tomorrow, we'll stay home. |
| Second | if + past, would + verb | imaginary or unlikely | If it rained here more, the grass would be greener. |
How to make the zero conditional
A zero conditional sentence has two parts. The if clause gives the condition, and the main clause gives the result. Both parts use the present simple: If you mix red and white, you get pink.
The if clause can come first or second. When it comes first, put a comma after it. When the main clause comes first, do not use a comma: You get pink if you mix red and white. The meaning does not change.
It is called zero because it is the most basic type. There is no will and no would, only the present simple.
If you press this button, the machine starts.
If babies are hungry, they cry.
My dog barks if someone knocks on the door.
If you don't eat breakfast, you get hungry by ten.
Facts and science
We use the zero conditional for general truths and scientific facts: things that always happen when a condition is true. The result is certain, not a guess.
These sentences are not about one moment. They are about how the world works, so you can often replace if with when and the meaning stays the same.
If you heat ice, it melts.
Metal expands if you heat it.
If you don't recharge a battery, it dies.
If people don't sleep enough, they find it hard to concentrate.
Habits, routines and personal truths
The zero conditional also describes things that always happen in your life or in a situation: your habits, your reactions and how things work at your job or at home.
These are true for you, not for everyone, but they are still regular and predictable. In this use, if means whenever or every time.
If I drink coffee after six, I can't sleep.
If my sister is stressed, she goes for a run.
If it's sunny on Sundays, we have lunch in the garden.
If the boss is away, the office is much quieter.
Instructions and advice
A very common variation uses an imperative in the main clause: If + present simple, imperative. We use it to give instructions, rules and advice for a type of situation: If you feel sick, stay at home.
You see this pattern on signs, in manuals and in emails at work. Learn more about commands in imperatives.
If the alarm goes off, leave the building immediately.
If you have any questions, call me.
Don't touch the oven if it's on.
The main clause comes first, so there is no comma.
If you aren't sure, ask the teacher.
If or when? Zero or first conditional?
In the zero conditional, if and when usually mean the same: If you heat water, it boils. When you heat water, it boils. Both are general truths.
The first conditional is different. It talks about one specific situation in the future, and the result uses will: If it rains tomorrow, we'll stay home. Compare: If I eat too much, I feel sick (always true for me) and If I eat all this cake, I'll feel sick (this cake, now).
To say the opposite condition, you can use unless, which means if not: Plants die unless they get water. See unless and provided that.
When you heat chocolate, it melts.
When and if mean the same here.
If you leave milk out of the fridge, it goes bad.
If you leave that milk out, it will go bad.
First conditional: one specific carton of milk.
The plant dies unless you water it.
In real life
In everyday conversation, people use the zero conditional to explain how things work, to talk about their habits and to give quick advice. Phrases like If you ask me (in my opinion) and If you think about it are also common in speech.
Remember: do not use will in the if clause. Say If it rains, not If it will rain. This rule is the same for the first conditional.
If you turn left here, you come to the station.
If I'm tired, I get a bit grumpy. Sorry!
If you ask me, it's too expensive.
A fixed phrase meaning in my opinion.
What happens if I miss the last train?
Common mistakes
If you will heat ice, it melts.
If you heat ice, it melts.
Do not use will in the if clause. In the zero conditional, both parts use the present simple.
If you heat ice, it will melt always.
If you heat ice, it melts.
For general truths, the result uses the present simple, not will. The present simple already shows that it is always true.
If water boil, it make steam.
If water boils, it makes steam.
Water is it, so both verbs need -s. The normal present simple rules still apply in conditionals.
Plants die, if they don't get light.
Plants die if they don't get light.
When the main clause comes first, we don't put a comma before if.
If I am drinking coffee late, I don't sleep.
If I drink coffee late, I don't sleep.
Habits and general truths use the present simple, not the present continuous.
Practice quiz
10 questions. Pick an answer to see if it is right and why.
1. If you ___ water to 100 degrees, it boils.
2. If you mix blue and yellow, you ___ green.
3. Choose the correct sentence.
4. Which word can replace if in If you heat ice, it melts without changing the meaning?
5. If you have any problems, ___ me.
6. Which sentence needs a comma?
7. Which sentence is a zero conditional?
8. If my brother ___ tired, he gets very quiet.
9. What does If I eat late, I don't sleep well mean?
10. Plants die ___ they get enough water.
0 of 10 answered
Show all answers
- heat
- get
- If it rains, the ground gets wet.
- when
- call
- If I'm late my boss gets angry.
- If you don't water plants, they die.
- is
- This happens every time I eat late.
- unless
See what the A2 English course covers, or test your level first.
People also ask
What is the zero conditional used for?+
It is used for things that are always true when a condition happens: scientific facts, general truths, habits and instructions. For example, If you heat ice, it melts, or If I'm stressed, I go for a walk.
What is the difference between the zero and the first conditional?+
The zero conditional is about general truths and uses the present simple in both parts. The first conditional is about one specific future situation and uses will in the result: If it rains tomorrow, I'll stay home.
Can I use when instead of if in the zero conditional?+
Yes, usually. In the zero conditional, if and when both mean every time this happens. When sounds more certain that the situation happens; if can suggest it does not happen often.
Do I need a comma in a zero conditional sentence?+
Use a comma when the if clause comes first: If you're cold, close the window. Do not use a comma when the main clause comes first: Close the window if you're cold.
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