Lee and Balsamo started working on the song during a camp session in Florida which lasted for several months; Lee played the music she had imagined for the song in her room while Balsamo could overhear it from his while simultaneously working on a very different "heavy riff". Upon hearing his work, Lee proposed that they mix both pieces together which led to the conception of "Call Me When You're Sober". According to the sheet music published by Alfred Publishing on the website Musicnotes.com, "Call Me When You're Sober" was written in the key of E minor. It is set in common time and performed in a moderately fast tempo of 96 beats per minute for a total length of 3 minutes and 34 seconds. Lee's vocal range in the song spans from the low musical note of G3 to the high musical note of Eb5. Kelefa Sanneh of "The New York Times" identified numerous different genres present in "Call Me When You're Sober" such as nu metal, symphonic rock and electropop. The song starts off as a piano ballad, progresses into a hard rock song with an orchestral pop-infused chorus and contains a bridge before the last chorus. The singer's vocals are doubled for the second verse of the song.