First conditional: if + present, will 📕

We use the first conditional for things that are possible or likely in the future.

Form

The two parts can change places. Then we do not need a comma:

I will stay at home if it rains.

Do not use will after if

✗ If it will rain, I will stay at home.

✓ If it rains, I will stay at home.

Unless = if not

I won't go unless you come with me.

I won't go if you don't come with me.

Zero conditional: facts that are always true

With general truths, use the present simple in both parts:

If you heat ice, it melts.

If I drink coffee late, I can't sleep.