Tennis

Overview

One or two players a side hit a ball over a net into the opponent's court. The scoring system is the part everyone needs to look up, and it is genuinely peculiar.

This entry is checked against the ITF Rules of Tennis 2026, the International Tennis Federation's own document. Rule numbers below are the ITF's.

1. The court

Element	Dimension
Length	23.77m
Width, singles	8.23m
Width, doubles	10.97m
Net at the posts	1.07m
Net at the centre	0.914m
Service box	6.4m from the net, half the singles width

The tramlines — the corridors between singles and doubles sidelines — are out in singles and in for doubles. The service boxes are the same size in both.

A ball touching any part of a line is good.

2. Scoring a game

Points won	Called
0	Love
1	15
2	30
3	40
4	Game

The sequence skips 45 for 40 — probably a verbal shortening that stuck.

At 40–40 the score is deuce. From deuce a player must win two consecutive points: the first gives them advantage, the second the game. Lose the point at advantage and it returns to deuce, indefinitely.

The server's score is always called first. "Thirty–fifteen" means the server leads.

Some competitions use no-ad scoring, where a single point at deuce decides the game and the receiver chooses the side.

3. Scoring a set

First to six games, provided they lead by two. At 6–6 a tiebreak is played.

In a tiebreak, points are counted normally — one, two, three. First to seven with a two-point margin.

• The player whose turn it is to serve serves the first point from the deuce court.
• The opponent then serves two points, and service alternates every two points thereafter.
• Players change ends every six points.

The set is recorded 7–6.

4. Scoring a match

The ITF rules allow a match to be best of three or best of five sets (Rule 6) and make no distinction between men and women anywhere — match length is left to each event.

At the four Grand Slams, the 2026 Official Grand Slam Rule Book narrows it down:

All men's singles Main Draw matches in Grand Slam Tournaments shall be the best of five (5) sets. All other matches shall be the best of three (3) sets unless otherwise determined by each Grand Slam Tournament.

So best of five applies to men's singles main-draw matches only. Women's singles, men's qualifying and doubles are best of three by default. Elsewhere on the tours almost everything is best of three.

The deciding set varies, and this has changed recently:

The ITF sets out three formats and lets an event choose between them before play:

Format	How it ends
Tie-break set	Tiebreak to 7 points at 6–6, by a margin of two
Match tie-break (10 points)	Replaces the final set entirely. First to 10, by two, after a 120-second set break
Advantage set	No tiebreak. Played on until someone leads by two games

All four Grand Slams now settle a final set with a 10-point match tie-break, and most tour events use a 7-point tiebreak at 6–6.

The advantage set has not been abolished. It is still in the ITF rules as a format an event may agree to use, and the rules even specify what to do when a tiebreak is started in error in an advantage set (Rule 27f). What has gone is its use in the deciding set at the top of the game — the change that followed the 70–68 final set of Isner–Mahut at Wimbledon in 2010.

5. Serving

The server stands behind the baseline, between the centre mark and the sideline, and serves diagonally into the opposite service box.

Service begins in the right (deuce) court and alternates each point.

Two attempts are allowed. A failed first serve is a fault; two is a double fault and loses the point.

Faults

• The ball lands outside the correct service box
• The server misses the ball entirely when attempting to strike it
• A foot fault — touching the baseline, the court, or the wrong side of the centre mark before striking the ball

Tossing the ball and catching it without swinging is not a fault.

Lets

A serve that touches the net cord and still lands in the correct box is a let and is replayed. There is no limit to consecutive lets, and a let on a second serve replays only the second serve.

6. Play

Players alternate hitting the ball after no more than one bounce on their side.

A player loses the point if they:

• fail to return the ball before it bounces twice
• hit the ball out, or into the net
• touch the net, post, or the opponent's court while the ball is live
• are struck by the ball, or it touches anything they wear or carry
• hit the ball before it crosses to their side
• deliberately hit the ball twice
• catch or carry the ball on the racquet

You may reach over the net to play a ball that has bounced on your side and spun back over, provided you do not touch the net.

A ball hit around the outside of the net post, below net height, is good if it lands in.

7. Changing ends

Players change ends after the first game, then after every subsequent odd-numbered game — so after games 1, 3, 5 and so on — and at the end of each set if the total number of games is odd.

In a tiebreak, ends change every six points.

8. Doubles

Partners choose who serves first in each set, and the order is fixed for the set. Receiving order is likewise fixed — a player who receives in the deuce court receives there for the whole set.

Either partner may return any ball once the point is live, but the designated receiver must take the serve. A serve striking the receiver's partner is a point to the serving side.

Switching hands

Entirely legal. You may move the racquet from one hand to the other at any moment, mid-rally or between points, as often as you like. Ambidextrous players occasionally do it to avoid a backhand. There is no rule against it.

Commonly argued

• A ball on the line is in. Any part of the ball touching any part of the line.
• A let serve is replayed, not a fault, and there is no cap on repeats.
• You may reach over the net, but only for a ball that has bounced back over by itself, and you must not touch the net.
• A ball hitting the net post and landing in is out in singles.
• A racquet leaving your hand is not automatically a fault — if the ball was legally returned before the racquet let go, the point stands.
• You cannot volley a serve. A returned serve taken before it bounces loses the point.
• The server's score is called first, always.
• Ends change after every odd game, and at the end of a set only when that set's total game count was odd. After a 6–2 set the players change at the end of the first game of the next set instead (Rule 10).
• Only men's singles main-draw matches at the Slams are best of five. Men's doubles and qualifying are best of three by default, like all women's matches. The ITF rules themselves treat men and women identically.
• The advantage set still exists in the ITF rules. It is no longer used for deciding sets at the Slams, which is a different thing from being abolished.