On January 4, 1936, Billboard magazine published its first music hit parade and on July 20, 1940 the first Music Popularity Chart was calculated. Since 1958 the Hot 100 has been published, combining single sales and radio airplay

The Pop 100 is a songs chart created in February 2005 and released weekly by Billboard magazine in the United States. It ranks songs based on mainstream radio airplay, singles sales, and digital downloads.

The chart was created as an answer to criticism of the Billboard Hot 100, the most popular Billboard singles chart. Many complained that the Hot 100 was biased against non-rhythmic songs, making it difficult for a pop, rock, or country song to reach the top ten. In fact, every number-one in 2004 was by a hip-hop or R&B artist. To illustrate another extreme, at the time the Pop 100 was first published, only one country act in the previous 20 years had reached #1 on the Hot 100 - Lonestar in 2000 with "Amazed"; Carrie Underwood would hit #1 later in 2005 with "Inside Your Heaven".

When the Pop 100 was first published, the Hot 100 changed its format as well. Digital downloads were incorporated into the equation which tabulates a song's rank on the chart. Prior to this, only radio airplay and singles sales were used to determine positions.

A Pop 100 Airplay chart was created alongside the new Pop 100. It measures mainstream radio airplay.