What is the equivalent of an 1/8th inch fitting in a "AN" fitting?

I'm in the middle of upgrading my brakes and need 2 fittings but I need flare fittings to connect lines together also known as "AN" fittings. I've found out that the fittings need to be 1/8th but I don't know what that would be in "AN" so if someone could tell me I would really appreciate it.