This arrangement of Happy Birthday is written in the key of concert D, so that all string instruments can play the song together. Select a link below for a free printable PDF of the song for your instrument. If you are looking for the piece in a different key, would like to see the chords for the song, or would like to find out about its history, visit the main Happy Birthday lead sheet page. The band arrangement of Happy Birthday is in the key of E flat, so if you want to combine string instruments with woodwinds and brass, select your desired key on that page. To determine the correct key for transposing instruments, visit the transposition chart page.