The rule as a picture, 5 multiple-choice questions, 3 sentences to correct and a short writing task. Free to print and copy for your class or for self-study.
Want the explanation first? Read the If vs When lesson
Use if when you're not sure something will happen: If I see Ana, I'll tell her. Use when when you're sure it will: When I see Ana tomorrow, I'll tell her. Both take the Present Simple for the future, not will.
If I see Ana, I'll tell her.
When I see Ana, I'll tell her.
Write two sentences about your own life: one with If and one with When. Then explain the difference to a partner.
Answers will vary. Check that each sentence follows the rule on page 1, or paste them into Clarigram to have them checked.