The UK Singles Chart is compiled by The Official Charts Company (OCC) on behalf of the British record industry. The full chart contains the weekly top-selling 200 single recordings in the United Kingdom, based upon combined record sales and download numbers. However, some media outlets only list the Top 40 (such as the BBC) or the Top 75 (such as Music Week magazine) of this list. Around 6,500 British retail outlets contribute sales data, as well as most UK online digital-download stores. Unlike charts in the United States, no airplay statistics are used for the official UK Singles Chart. The chart week runs from 00:01 Sunday to midnight Saturday, with most UK digital singles being released on Sundays (followed by CD releases on Monday).

The Top 40 chart is first released on Sunday afternoons by BBC Radio 1 before it is posted on the OCC's website,^{[citation needed]} with the top 75 being printed in Music Week magazine the following Monday and the top 200 appearing in the independent newsletter UKChartsPlus on Wednesdays. It is also published online. Radio 1 broadcasts a Top 40 countdown on Sundays from 16:00 to 19:00. The show had various presenters over the years, including Tommy Vance, Mark Goodier, Bruno Brookes and Alan Freeman whose Pick Of The Pops was the chart show from the 1960s into the early 1970s. Since October 2007, Reggie Yates has presented the chart show (until September 2009 with Fearne Cotton). Cotton was the first permanent female presenter of the Official Chart Show. A rival chart show, The Big Top 40 Show is based on downloads and commercial radio airplay and is broadcast on 140 commercial local radio stations. According to the Official Charts Company, the official British singles chart was the New Musical Express chart from 1952 to 1960, the Record Retailer chart from 1960 to 1969 and the Official UK Singles Chart since 1969.

A record chart is a ranking of recorded music according to popularity during a given period of time. Examples of music charts are the Hit parade, Hot 100 or Top 40.

There are lots of different criteria used in different charts used to reflect popularity, commonly: sales of records, cassettes and compact discs; the amount of radio airplay; and (recently) the number of downloads.

Some charts are specific to a particular musical genre and most to a particular geographical location (although download charts are not easily pinned down in this way). The most common period of time covered by a chart is one week with the chart being printed or broadcast at the end of this time. Summary charts for years and decades are then calculated from their component weekly charts. Component charts have become an increasingly important way to measure the commercial success of individual songs.

A chart hit is an extremely popular recording, identified by its inclusion in a chart that uses sales or other criteria to rank popular releases. Chart-topper and related terms (like No. 1 hit, top of the charts, chart hit, and so forth) are widely used in common conversation and in marketing, and are loosely defined. In North America, the weekly charts from Billboard magazine are most often referenced (quite often internationally, as well), particularly the Billboard Hot 100 singles chart and Billboard 200 album chart, although there are many other charts and sources. Because of its value in promoting recording artists and releases, both directly to the consumer, and by encouraging exposure on radio, TV other media, chart positioning has long been a subject of scrutiny and controversy. Chart compilation methodology and data sources vary, ranging from buzz charts based on opinions of various experts and tastemakers, to charts that reflect empirical data such as retail sales. Therefore, a chart-topper may be anything from an "insiders' pick" to a runaway seller.