What is the best way to tell my parents I`m an atheist?

[Matt]

I turned 20 in February and had my doubts about Christianity since middle school, and finally came to the conclusion that I was an atheist when I was around 17. I`m in college obviously but I commute to school so I still live at home, which might pose a small problem. I want positive ways to tell them, nothing like "What you worship is bullshit!" Even though I agree with that, it`s not something you`re supposed to do, especially to your parents. I`m almost positive the rest of my family knows cause I`ve given small hints on social media, and I haven`t told my parents yet for obvious reasons. (pretty difficult) Thanks for the responses.