The object of tennis is elementary: strike the ball into the opponent's court so they cannot legally return it, and do it more often, at the right moments, than they do to you. A point ends the instant a ball bounces twice, is hit into the net, or lands outside the lines. Everything else — the serve, the surfaces, the four-hour epics — is built on that single exchange, repeated until one side has assembled enough points to win.
What makes tennis distinctive is that those points are not simply added up. They nest inside games, games inside sets, and sets inside a match, so winning the biggest points matters far more than winning the most points — a player can take more total points across a match and still lose it. One player serves for an entire game before handing over, and because there is no clock, a contest runs until the required sets are won, which is why no scoreline in tennis is ever truly safe.
Scoring at a glance
Core rules
The serve
Every point begins with a serve struck from behind the baseline, alternating between the deuce (right) and advantage (left) courts. The ball must clear the net and land in the service box diagonally opposite; the server has two attempts, and missing both is a double fault that loses the point. A serve that clips the net cord and still lands in the correct box is a let and is replayed without penalty. The same player serves an entire game before the roles switch, which is why holding your own serve is the baseline expectation of competitive tennis.
Points and deuce
Within a game, points are counted love (zero), 15, 30 and 40. Reach four points with a two-point margin and the game is yours. At 40-40, called deuce, a player must win two points in a row: the first earns advantage, the second wins the game, and losing it returns the score to deuce. Games can therefore swing back and forth indefinitely, which is why a single service game can stretch past twenty points and, in a tight set, decide everything. Winning a game your opponent served is a break of serve, the pivotal event of most sets.
Sets
A set is won by the first player to six games with a lead of at least two, such as 6-3 or 7-5. If the score reaches 6-6, a tiebreak almost always decides it. Winning the required number of sets wins the match. Because two clear games are needed, a set level at 5-5 must be taken 7-5 or go to a tiebreak, and a set that reaches 6-5 can still be pegged back to 6-6. This margin-of-two rule is what makes the break of serve the currency every rally is ultimately spent on.
The tiebreak
At 6-6 in a set a tiebreak resolves it. Points are counted 1, 2, 3, and the first to seven points with a two-point margin wins the set 7-6. Players alternate serves — one point, then two at a time — and change ends every six points. If the tiebreak reaches 6-6, it continues until someone leads by two. Since 2022 all four Grand Slams settle their deciding set with a longer 10-point tiebreak at 6-6, standardising a format that had previously differed at every major and could otherwise run on without limit.
In, out and the ball in play
A ball touching any part of a line is in; one landing wholly beyond the sidelines or baseline is out. The ball may be played after one bounce or volleyed before it bounces, but letting it bounce twice loses the point. A player may not touch the net, reach over it before the ball has crossed, or interfere with a ball still in play. Since 2025 much of the professional tour uses electronic line calling, with automated ball-tracking replacing human line judges on every surface except clay, where the ball's mark can still be read.
Serving order and changing ends
A racquet spin or coin toss before the match decides who serves first or which end to take. Players change ends after the first game and then after every two games, and every six points in a tiebreak, so neither is disadvantaged too long by sun or wind. In doubles, each pair fixes a serving order for the set and the partners alternate service games, while the receiving side chooses which player takes each service court and keeps that arrangement throughout the set.
The singles and doubles court
The court is 78 feet long and, for singles, 27 feet wide. Doubles widens it to 36 feet by bringing the tramlines — the alleys down each side — into play. The net stands three feet high at the centre and three and a half feet at the posts, and the service boxes reach 21 feet back from the net. Knowing which lines are live is fundamental: a ball into the tramlines is good in doubles but out in singles, and the extra width completely changes doubles positioning and angles.
Best of three and best of five
Women play best-of-three sets at every level, as do men on the regular tour. Only at the four Grand Slams do men play best-of-five, needing three sets to win in matches that can pass four or five hours and test endurance as much as skill. Since 2022 all four majors resolve a deciding set with a 10-point tiebreak once it reaches 6-6, ending the era of open-ended final sets that produced scorelines like the 70-68 fifth set of the 2010 Isner-Mahut marathon at Wimbledon.
Fouls & penalties
Foot fault
The server must keep both feet behind the baseline, and inside the imaginary extensions of the centre mark and sideline, until the racquet meets the ball. Touching or stepping over the line before contact is a foot fault, ruled as a service fault; commit it on a second serve and the point is lost. Foot faults are policed strictly in professional tennis, and a late-set foot fault has swung more than one major final.
Double fault
The server has two attempts to land a serve in the correct box. Miss both — into the net, wide, or long — and it is a double fault, conceding the point outright with no rally. Because a double fault is entirely self-inflicted, it carries unusual psychological weight, especially on break or match points, and a player's second-serve reliability under pressure is one of the clearest measures of competitive nerve.
Double bounce and bad return
A player must return the ball before its second bounce and send it, over the net, into the opponent's court. Letting the ball bounce twice, netting it, or hitting it beyond the lines all lose the point, as does striking a ball before it has crossed to your side of the net. A volley taken before the served ball has landed, or a shot that strikes a permanent fixture before bouncing, likewise does not count.
Hindrance
A player may not deliberately or needlessly distract an opponent. A shout during a rally, a grunt loud enough to mask the sound of the ball, or a second ball spilling from a pocket onto the court can be called a hindrance. A deliberate hindrance loses the point; an unintentional one — a hat blown off by the wind — usually leads to the point being replayed at the umpire's discretion.
Touching the net or reaching over
A player loses the point if they, their racquet, or their clothing touch the net, the posts, or the opponent's side of the court while the ball is live. A player also may not volley a ball before it has crossed to their side of the net. The single exception: if heavy backspin carries a ball back over the net on its own, the striker is allowed to reach across and play it.
Time violation and code of conduct
A shot clock allows 25 seconds between points; exceeding it brings a warning and then the loss of a serve or point. Separate code-of-conduct offences — racquet abuse, ball abuse, audible or visible obscenity, unsportsmanlike conduct, or coaching outside the rules — escalate from a warning to a point penalty, a game penalty, and finally default, applied cumulatively across the match by the chair umpire.
Match format
A tennis match has no clock and cannot be drawn: play continues until one side has won the required sets — two in a best-of-three, three in a best-of-five. Within each set the decisive currency is the break of serve, holding your own delivery while stealing one of your opponent's. Because holding serve is the norm at professional level, a single break often settles a set, which is why break points carry such disproportionate weight and why a scoreline can look comfortable yet hinge on two or three points.
When a set reaches 6-6 a tiebreak resolves it, and since 2022 the four Grand Slams have unified their deciding sets around a 10-point tiebreak at 6-6, closing the age of marathon final sets. A winner is declared the moment the last point is won — there is no overtime beyond the required margin of two, and no tie. That nested structure, points inside games inside sets, is precisely what lets a trailing player reset after every point and mount the comebacks that define the sport.
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