 "3" debuted at number fifty on the Australian Singles Chart on October 12, 2009, with only two days of digital sales. It peaked at number six on the week of October 26, 2009. "3" has been certified platinum by the Australian Recording Industry Association (ARIA) with sales of over 70,000 copies. On October 12, 2009, the song debuted at number sixteen in New Zealand, making it her highest chart debut since "Womanizer". On its fifth week on the chart, "3" reached its peak position at number twelve. On the UK Singles Chart, "3" debuted at number seven on November 16, 2009, becoming Spears' twentieth top ten hit on the chart. According to The Official Charts Company, the song has sold 145,000 copies there. "3" achieved similar success throughout Europe reaching the top ten in Belgium (Wallonia), Czech Republic, Finland, Norway, Sweden as well as the top twenty in Austria, Belgium (Flanders) and Denmark.
