The song received critical acclaim from music critics , who hailed its musical diversity . It was serviced to mainstream radio in the United States and Italy ; a 12-inch vinyl of the single was released for Record Store Day 2014 . The song became Paramore 's highest peaking single on the US '' Billboard '' Hot 100 , peaking at number 10 and received ' double platinum ' certification from the RIAA having sold over two million singles . Internationally , the song garnered moderate commercial outcomes , reaching the top 40 of Australian , Canadian and Venezuelan charts . On February 8 , 2015 , the song won the Grammy Award for Best Rock Song at the 57th ceremony , becoming Paramore 's first Grammy win , and making Williams the first woman to score that honor since Alanis Morissette in 1999
57th ceremony
57th Annual Grammy Awards
Ain't It Fun (Paramore song)