When or If?

When do we use when and if?

WordExplanationExample
whenyou are sure that something is going to happenWhen I’m in Rome, I’ll visit you. (I’m sure, that I’m going to Rome.)
ifyou are not sure that something is going to happenIf 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.