not pulling out on the pill?

i’m on BC pills and have been for almost 2 years. i’m pretty good about regularly taking them and have never had a pregnancy scare. for the first time ever a couple days ago i let a guy finish inside me. i’m not super worried about it because i know the pill is largely very effective but eve never gives me a % likely to get pregnant today because i am on the pill and i would just like to know at what point in my cycle on birth control would it be more likely to fail if he didn’t pull out