<P> A tennis court is the venue where the sport of tennis is played . It is a firm rectangular surface with a low net stretched across the center . The same surface can be used to play both doubles and singles matches . A variety of surfaces can be used to create a tennis court, each with its own characteristics which affect the playing style of the game . </P> <P> Tennis is played on a rectangular flat surface, usually of grass, clay or hard material . The dimensions of a tennis court are defined and regulated by the International Tennis Federation (ITF) governing body and are written down in the annual' Rules of Tennis' document . The court is 78 feet (23.77 metres) long . Its width is 27 feet (8.23 metres) for singles matches and 36 feet (10.97 metres) for doubles matches . The service line is 21 feet (6.40 metres) from the net . Additional clear space around the court is needed in order for players to reach overrun balls for a total of 60 feet (18 metres) wide and 120 feet (37 metres) long . A net is stretched across the full width of the court, parallel with the baselines, dividing it into two equal ends . The net is 3 feet 6 inches (1.07 metres) high at the posts, and 3 feet (0.91 metres) high in the center . The net posts are 3 feet (0.91 metres) outside the doubles court on each side or, for a singles net, 3 feet (0.91 metres) outside the singles court on each side . </P> <P> Tennis is played on a variety of surfaces and each surface has its own characteristics which affect the playing style of the game . There are four main types of courts depending on the materials used for the court surface: clay courts, hard courts, grass courts and carpet courts . The International Tennis Federation (ITF) lists different surfaces and properties and classifies surfaces into one of five pace settings: </P>

What is the standard size of tennis court
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