"Seven Nation Army" is an alternative rock and garage rock song with a length of three minutes and 52 seconds. According to sheet music published by Universal Music Publishing Group, it is composed in the key of E minor in common time with a tempo of 120 beats per minute. The title of the song comes from when Jack was a young kid in Detroit. He misheard "The Salvation Army" as "The Seven Nation Army". Years later, that happy accident had evolved into the title.