The Billboard Hot 100 is a chart that ranks the best-performing songs in the United States.
Twenty-four acts reached number one in 2021, nine of whom earned their first number-one single: Olivia Rodrigo, Daniel Caesar, Giveon, Silk Sonic, Anderson .Paak, Polo G, The Kid Laroi, Future, and Jack Harlow.
Their single "Butter" is the longest running number-one song of 2021, spending ten weeks atop the chart.
Rodrigo's "Drivers License" was 2021's longest running number-one single by a female artist, with eight consecutive weeks atop.
Taylor Swift scored her career's eighth number-one song this year with "All Too Well (Taylor's Version)", which broke the 49-year-old Hot 100 record of Don McLean's "American Pie" (1972) to become the longest song of all time to top the chart, clocking at 10 minutes and 13 seconds.