“Part of Me” was a commercial success. It was the twentieth song to debut at number one on the Billboard Hot 100, Perry’s seventh number-one single on the chart, and her ninth consecutive number-one single on the Billboard Hot Dance Club Songs chart. The single debuted at number one in the United Kingdom and Canada, and has been certified Platinum in the United States, Australia and New Zealand
The song was a major hit internationally, reaching number one in 16 countries, including Australia, Austria, Canada, Germany, Italy, New Zealand, Sweden, Turkey, and the Netherlands, as well as staying at number one for eight consecutive weeks on the Billboard Pop 100 chart. The song charted in the Top Three on the Billboard Hot 100 and spent 13 weeks at number one in Canada.