Au Cas Où - French Expression Explained

man with umbrella looking at man standing in the rain
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The French expression Au cas (pronounced [o ka oo], note that there is no liaison between cas and ) literally translates to "in the case where"

Explanation and Examples

The French expression au cas où is exactly equivalent to "(just) in case" in English. You can use it in front of a subject plus verb in the conditional, in which case its register is normal to formal. The more interesting - and informal - usage is when it's tacked on to the end of a sentence.

If you don't already use au cas où regularly, you soon will.

   Au cas où il rentrerait avant nous, je vais lui laisser un mot.
   (Just) in case he gets home before us, I'm going to leave him a note.

   Apporte un parapluie, au cas où il pleuvrait.
   Bring an umbrella, (just) in case it rains.

   Apporte un blouson, au cas où.
   Bring a jacket, just in case.

Synonymous Expressions

For au cas où + conditional:

  • dans le cas où
  • des fois que
  • pour le cas où

For the informal au cas où at the end of a sentence:

  • à tout hasard
  • pour le cas où