The song reached number three on the "Billboard" Hot 100 and number one on American pop radio and is her second best-selling digital song in the United States, having sold over 3.2 million downloads as of July 2016. On a global scale, "Circus" was one of the top 10 best selling songs of 2009 with 5.5 million digital copies sold that year across the world, according to the IFPI.