Why is tennis 15/30/40?

The unique 15, 30, and 40 scoring system in tennis is believed to have originated from a medieval French system, historically linked to the use of clock faces.

The Historical Roots of Tennis Scoring

The most widely accepted theory behind tennis scoring ties back to the Middle Ages, when early versions of the sport, such as jeu de paume, were played. During this period, scores were reportedly tracked using physical markers, often resembling clock faces that went from 0 to 60.

The Clock Face Connection

Imagine a score being kept on a dial, much like a clock:

• For each point won, the pointer would advance a quarter of the way around the clock face.
• The first point moved the pointer from 0 to 15.
• The second point advanced it to 30.
• The third point would move it to 45.
• The final point, winning the game, would bring the pointer to 60.

The Mystery of "40"

The most distinctive aspect of tennis scoring is the shift from "45" to "40." When the use of these physical clock faces for scoring eventually faded out, the "forty-five" point was somehow truncated or shortened to "forty." This change likely occurred to simplify and speed up the calling of scores during play, leading to the peculiar yet iconic "15, 30, 40" sequence that defines tennis today.

Modern Tennis Scoring Progression

This historical progression forms the foundation of how points are counted in a modern tennis game. A player must win at least four points and have a lead of at least two points over their opponent to win a game.

Here's how the points are typically called out in a single game:

If both players reach 40 (meaning they have both won three points), the score is called "deuce." From deuce, a player must win two consecutive points to win the game. The first point won after deuce gives that player "advantage," and if they win the next point, they win the game. If they lose the next point, the score returns to deuce.