Ça m'est égal: This is the safest way to say “I don’t care in French. It literally means “It’s equal to me”.
Je m’en fiche: This is the phrase that most people use. It is not vulgar, but it carries more power than the first phrase.
Je m’en fous: This phrase is vulgar, equivalent to saying, “I don’t give a shit.”
Je m’en bats les couilles: This is vulgar, and stronger than the previous. However, this is a bit long and unnecessary, and most people use “Je m’en fous” instead.
J’en ai rien à foutre: This is vulgar, and the same rules apply as the last.
