learn the rule: then / than

  • then is an adverb, usually indicating the time at which an event has occurred or will occur, as an addition, or to add emphasis
    • I will find your sock, then I will find your potato.
    • If you don't give me your potato, then I will be forced to eat your sock.
    • I ate your potato and then I ate your sock.
  • than is a conjunction & preposition, most commonly in comparisons
    • You're more ugly than everyone.
    • There's no-one more stupid than you.
  • The two are not interchangeable.
  • Getting it wrong makes you look stupid. And ugly.