The Zero Conditional: How to Talk About Facts and General Truths

What is the zero conditional?

The zero conditional is used to talk about things that are generally true, especially for laws and rules.

It is used to make statements about the real world, and often refers to general truths, such as scientific facts. In these sentences, the time is now or always and the situation is real and possible.

Think of the zero conditional as the "facts pattern." When you want to say that something always happens if a condition is met—every single time, without exception—you use this structure.

If you heat water to 100°C, it boils.

If you mix red and blue, you get purple.

If people don't eat, they become hungry.

Each of these statements describes a result that is certain and unchanging.

How to form the zero conditional

The structure is: If + present simple, present simple. Both clauses (that is, both parts of the sentence) use the present simple tense.