List of Billboard number-one singles of the 1940s

Billboard number-one singles chart (which preceded the Billboard Hot 100 chart), which was updated weekly by the Billboard magazine, was the main singles chart of the American music industry since 1940 and until the Billboard Hot 100 chart was established in 1958. Before the Billboard Hot 100 chart was established in August 1958, which was based on a formula combining sales data of commercially available singles and airplay on American radio stations, the Billboard used to publish several song popularity charts weekly.

Source: Wikipedia — List of Billboard number-one singles of the 1940s (CC BY-SA 4.0)