What Does Top 40 Mean?

The origin of the term, its history, and its meaning today

Casey Kasem
Casey Kasem.

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Top 40 is a term used frequently in the music world. It is generally used as a label for mainstream pop music, particularly as played on the radio. Read on for the history and the role of Top 40 in the world of pop music.

The Origins of Top 40

Before 1950, radio programming was different from what it is today. Most radio stations broadcast chunks of programming—possibly a 30-minute soap opera, then an hour of music, then 30 minutes of news, etc. Much of the content was produced elsewhere and sold to the local radio station. Local pop music hits were rarely played if at all. 

In the early 1950s, a new approach to programming music on the radio began. Nebraska radio broadcaster Todd Storz is credited with inventing the top 40 radio format. He purchased the Omaha radio station KOWH in Omaha with his father Robert in 1949. He noticed how certain songs were played over and over on local jukeboxes and received a strong positive response from patrons. He created a music-focused top 40 format that played the most popular songs frequently.

Todd Storz pioneered the practice of surveying record stores to determine which singles were the most popular. He bought additional stations to spread his new format idea. By the mid-1950s, Todd Storz coined the term "top 40" to describe his radio format.

Successful Radio Format

As rock and roll took over as the most popular genre of American music in the late 1950s, top 40 radio blossomed. Local radio stations would play top 40 countdowns of the most popular records, and radio stations began to use commercial jingles to aggressively promote their top 40 format. The legendary PAMS company from Dallas created jingles for radio stations across the country. Among the legendary top 40 radio stations of the late '50s and early '60s were WTIK in New Orleans, WHB in Kansas City, KLIF in Dallas, and WABC in New York.

American Top 40

On July 4, 1970, a syndicated radio show began called American Top 40. It featured host Casey Kasem counting down the top 40 hits each week from the Billboard Hot 100 singles chart. The creators of the show were unsure about its chances for success initially. However, the show soon became very popular and by the early 1980s, it was featured on over 500 radio stations across the U.S. and many more around the world. Through the weekly countdown show, millions of radio listeners became familiar with weekly record charts focusing on the 40 most popular hits in the country, not just their local area. The countdown helped spread knowledge of hit records quickly from coast to coast encouraging listeners to request that their local radio stations play new songs on the countdown.

In 1988 Casey Kasem left American Top 40 due to contract concerns and he was replaced by Shadoe Stevens. Angry listeners caused many radio stations to drop the program and some replaced it with a rival show called Casey's Top 40 created by Kasem. American Top 40 continued to slide in popularity and came to an end in 1995. Three years later it was revived with Casey Kasem once again hosting. In 2004 Casey Kasem left once again. This time the decision was an amicable one, and Kasem was replaced by American Idol host Ryan Seacrest.


Once national radio formats were established and played similar songs across the country, radio airplay became a major factor impacting sales of manufactured vinyl records. As a result, record labels began looking for ways to influence what songs were played in top 40 radio formats. They began to pay DJs and radio stations to play new records, particularly rock and roll records. The practice became known as payola.

Ultimately, the practice of payola came to a head in the late 1950s when the United States Senate began to investigate. Famed radio DJ Alan Freed lost his job, and Dick Clark nearly was implicated as well. 

Concern about payola returned in the 1980s through the use of independent promoters. In 2005 major label Sony BMG was forced to pay a $10 million fine for improperly making deals with chains of radio stations. 

Top 40 and Mainstream Pop Music

Top 40 as a radio format has had its ups and downs since the 1960s. The widespread success of FM radio in the 1970s with more widely varied programming caused the top 40 radio format to wane. It roared back with the success of "Hot Hits" formats in the late 1970s and early 1980s. Today top 40 radio has evolved into what is called Contemporary Hits Radio (or CHR). The model for focusing on a tight playlist of hit songs interspersed with news bits and aggressive promotion of the radio station has now become dominant across a wide number of musical genres. By the year 2000, top 40 as a term had evolved beyond referring simply to a radio format. Top 40 is now widely used to represent mainstream pop music in general.

In 1992 Billboard debuted its Mainstream Top 40 radio chart. It has also been called the Pop Songs chart. It is the chart intended to reflect the mainstream of pop music on the radio. The chart is compiled by detecting the songs played on a select panel of top 40 radio stations. The songs are then ranked according to popularity. Songs that rank below #15 on the chart and have spent more than 20 weeks on the chart overall are removed and placed on a recurrent chart. That rule keeps the list of songs more current.