Grammar › Conditionals › Zero Conditional
Zero Conditional
The zero conditional (if + present simple, present simple) is for things that are always true. Use it for:
- General truths and facts — If you heat ice, it melts.
- Rules, habits and instructions — If the light is red, you stop.
Both clauses use the present simple. You can usually replace 'if' with 'when' — the meaning barely changes.
How to form the zero conditional
| Clause | Verb form | Example |
|---|---|---|
| If-clause (the condition) | if + present simple | If you press this button, |
| Main clause (the result) | present simple | the machine starts. |
Both parts use the present simple. If the if-clause comes first, put a comma after it; if it comes second, no comma is needed.
When to use the zero conditional
1. General truths and facts
- If you mix blue and yellow, you get green.
- Water boils if you heat it to 100°C.
2. Habits and routines
- If I drink coffee late, I don’t sleep.
3. Rules and instructions
- If the alarm rings, leave the building.
⚠️ Typical error:
If you heat ice, it will melt.(a general truth) → Both clauses take the present simple: If you heat ice, it melts.
Common mistakes
1. Using ‘will’ in the zero conditional. A general truth uses the present simple, not will. If you don’t water plants, they will die (as a fact) → If you don’t water plants, they die.
2. Using ‘will’ in the if-clause. If you will press this → If you press this.
3. Adding a comma when the result comes first. Ice melts, if you heat it → Ice melts if you heat it.
✏️ Practice: Zero Conditional
1. If you heat ice, it ___.
2. If I ___ tired, I go to bed early.
3. Water ___ if you cool it to 0°C.
4. If the traffic light ___ red, cars stop.
5. If you ___ this button, the machine starts.
6. If people don't sleep, they ___ tired.
7. If the alarm ___, everyone leaves the building.
8. ___ you touch fire, you get burned.
9. Choose the sentence with the same meaning as: 'When you touch fire, you get burned.'
10. Choose the correct version of: 'If you will mix red and white, you get pink.'
11. Fill in the gap
If you mix red and blue, you ___ purple. (get)
Use the present simple.
12. Correct the mistake
If you don't water plants, they will die. (a general fact)
Type the whole corrected sentence.
13. Fill in the gap
What ___ if you mix red and yellow? (happen)
Use the present simple.
Frequently asked questions
What is the difference between the zero and first conditional?
The zero conditional is for things always true (If you heat ice, it melts). The first conditional is for a specific future possibility (If it rains tomorrow, I'll stay home).
Can I use 'when' instead of 'if'?
Yes — in the zero conditional they're almost the same: 'When/If you heat ice, it melts.'
Do I need a comma?
Use a comma when the if-clause comes first (If it rains, we stay in). No comma when it comes second (We stay in if it rains).
Which tense goes in each clause?
Both clauses use the present simple: if + present simple, present simple.
👩🏫 For teachers
CEFR objectives for “Zero Conditional”:
- Can form the zero conditional with the present simple in both clauses (CEFR A2).
- Can use it for general truths, rules and habits.
- Can distinguish it from the first conditional.
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