Zero Conditional If-Clauses in English Grammar

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What is the zero conditional?

Zero conditional sentences express things that always happen providing a certain condition is met. This condition is expressed in the if-clause. Both clauses contain the present tense.


If you heat water, it boils.

Ice cream melts if you leave it in the sun.

If you freeze water, you get ice.

When to use zero conditional if-clauses

We use zero conditional if-clauses to talk about:

  • facts
    If you heat water, it boils.
  • habits
    If it is warm, I go to the beach.
  • rules
    Children can ride the rollercoaster if they are over 140cm tall.

How to form the zero conditional

To form the zero conditional, we use the present tense in both the if-clause and the main clause.

If you heat water, it boils.

We can reverse the order of the clauses without any change in meaning.

If you take the bus, you need a ticket. = You need a ticket if you take the bus.

When the if-clause comes first, it is followed by a comma. If the order is reversed, we do not use a comma.

If I have time, I go to the gym after work. (comma after if-clause)
I go to the gym after work if I have time. (no comma)

If, when and whenever

Zero conditional if-clauses express almost the same meaning as time clauses with when and whenever. When emphasises the certainty of an action.

Harry feels better if he exercises. = Harry feels better when he exercises.

Whenever means at any time or every time when.

Whenever it is warm, I go to the beach.

Learn more about the difference between when and if.