When or If?

When do we use when and if?

Word Explanation Example
when you are sure that something is going to happen When I’m in Rome, I’ll visit you. (I’m sure, that I’m going to Rome.)
if you are not sure that something is going to happen If I’m in Rome, I’ll visit you. (I’m not sure, that I’m going to Rome.)

You can both use when and if when you talk about things that happen repeatedly (in generalizations).

  • When you heat ice, it melts.
  • If you heat ice, it melts.