I dont belive in God how do i tell my parents?

hello, i don't believe in God but i decided i will tell my parents and i don't know how to tell them my mom,grand father, and grand mother are VERY religious, my dad doesn't believe in God but i think we will not like it so please tell me how i should tell them and don't answer with telling me i should believe (im under 18 years old and most of my family is religious) also i i have gave them some obvious hints but they still don't know, thanks to every one and also please have deatils and help ful tips in your answer thanks again :)