The Top Forty or Top 40 is a music industry shorthand for the currently most-popular songs in a particular genre. When used without qualification, it typically refers to the best-selling or most frequently broadcast pop music songs. Other lists of hit songs may include a different number of entries, such as a "Top 50" or "Top 100".

The current top songs are tracked by a variety of trade publications, such as:

• Top 40 Mainstream, a chart of current popular songs in the United States compiled by Billboard Magazine, and its various predecessors
• UK Top Forty, a British version of the same concept.
• Dutch Top 40, the Dutch music chart.

Radio programs that highlight currently popular songs also refer to the "Top 40":

• Top 40 (radio format), a radio format based on playing the top 40 popular songs of the week (may or may not be based on Billboard's chart), also known as "contemporary hit radio."
• American Top 40, a weekly syndicated radio show originally hosted by Casey Kasem.

Further reading

• Durkee, Rob. "American Top 40: The Countdown of the Century." Schriner Books, New York City, 1999.
• Battistini, Pete, "American Top 40 with Casey Kasem The 1970s." Authorhouse.com, January 31, 2005. ISBN 1418410705.

Pop music