Tennis Line Rules

There are a variety of theories about the history of tennis. Some argue that the sport was originally invented by European monks in the 14th century, others say that is was played by the anceint Egyptians and Persians, and still others have alternative theories. Whatever the origins, tennis has evolved into a worldwide competitive sport. There are national and international tennis associations to set the standard rules for the game, including the rules that dictate the line play.

  1. Distances

    • A regulation tennis court is always 78 feet long and 36 feet wide. The lines for singles tennis, which uses a thinner court than doubles tennis, are drawn at 27 feet wide, instead of the 36 feet. There is also a line across the middle of the court, where the net separates one half from the other.

      According to X Sport, a court builders association, the vertical lines must be between one and two inches thick. The base lines, or the two horizontal lines across the two ends of the court, can be up to four inches thick. The center line should be two inches thick. On some surfaces the lines may need to be slightly adjusted, but they cannot vary from the necessary measurements by more than ¼ inch.

      For tournament regulations, there must be a minimum of 21 feet from each base line to any obstruction behind the line, such as a wall. In non-tournament play this distance can be as small as 18 feet—anything shorter than that can obstruct play.

      Similarly, no obstruction can be within 12 feet of the side lines.

    Ins and Outs

    • In tennis, players win or lose points almost exclusively on the basis of whether the ball lands in or out of the court, and the United States Tennis Association clearly outlines the rules regarding the ball and the lines.

      If any portion of the tennis ball touches the baseline or the sideline, the ball is in. The USTA sums it up by saying that if 99 percent of the ball is beyond the line and only one percent of the ball touches the line, the ball is still in.

      Remember that the sidelines are different depending on whether you are playing singles or doubles. For singles, the ball must touch the 27 foot line, while in doubles the ball must touch the sideline. On clay courts, the ball will leave a small mark on the court; on grass courts, the ball may leave a mark, or the call may be up to the judges or players.

    Judgment Calls

    • When players play for fun or in small tournaments, there will not always be judges around to call balls in or out. In these instances, it is up to players themselves to play on the honor system.

      USTA states that if a player is unsure about whether or not a ball has gone, he should always give the benefit of the doubt to his opponent.

      In doubles play, the player closest to the ball when it hits will generally call the ball in or out. However, if you can see that your partner has made the wrong call, it is your responsibility to correct it, so that the game is played fairly.