English: assume vs presume

Both are guesses. Assume is weaker (little or no evidence), presume is stronger (reasonable evidence). But how to remember which is which?


  • Assume = make a guess based on little or no evidence.
  • Presume = make an informed guess based on reasonable evidence.


  • When you ass-ume something, it's just a guess that you have pulled from your ass.
  • When you pre-sume something, you have some pre-knowledge or pre-information to support your guess.