I couldn't care less

US /aɪ ˈkʊdnt kɛr lɛs/

UK /aɪ ˈkʊdnt kɛr lɛs/

used to express that one does not care at all about something

•

He was complaining about his new car, but I couldn't care less.

•

Whether they come or not, I couldn't care less.