 On the Official German Charts, "Sweet but Psycho" debuted on October 26, 2018 at number 82, topping the chart for six weeks, and charting for 50 weeks.In Slovenia, it peaked at number one, eventually being ranked at number one on the 2019 year-end chart.In Poland, "Sweet but Psycho" topped the Polish Airplay Top 100 on the chart issued January 19, 2019, where it was certified diamond by the Associação Fonográfica Portuguesa (AFP) for track-equivalent sales of 100,000 units.