Everyday · Life · Sport
Why tennis counts 15, 30, 40 — and what exactly a tiebreak is.
Almost every confusing thing about tennis scoring comes from one fact: there are four scoring systems nested inside each other, and the commentary moves between them without saying so.
A tennis match is not scored on one scale. It is scored on four, stacked inside one another, and a broadcast will move between them mid-sentence without flagging the change. Once the stack is visible the rest is straightforward.
POINTS → win enough, you take a GAME
GAMES → win enough, you take a SET
SETS → win enough, you take the MATCH
TIEBREAK → a substitute for the ordinary game count
Winning more points than your opponent does not win the match. It is entirely possible — and happens at the highest level — to win more total points across a match and lose it, because points only matter within the game they belong to. A game won 40–0 and a game lost 0–40 are worth exactly the same on the level above: one game each.
That is the whole reason the system exists. It rewards winning at the right moments rather than accumulating.
Points: 15, 30, 40, and why the fourth has no number
Within a game the sequence runs love, 15, 30, 40, game. Zero is called love. The fourth point does not get a number — it ends the game instead, provided the margin is there.
The margin is the catch. A player must win by two points, and at 40–40 the score is called deuce rather than 40–40. From deuce, one point does not win the game; it produces advantage. Win the next point and the game is yours. Lose it and the score returns to deuce, and can do so indefinitely.
40–40 → deuce
win a point → advantage
win again → game
lose it instead → back to deuce
One thing worth saying plainly, because it is repeated confidently everywhere and is not established: the origin of 15, 30 and 40 is debated, not settled. The most popular explanation involves a clock face, with 40 as a shortening of 45. Others point to early scoring by increments on a court divided into segments, or to the currency and games of the period. These are accounts of varying plausibility, and no one of them should be presented as proven.
Games and sets: six is not enough on its own
A set goes to the first player to win six games — but again with a two-game margin. Six games to four takes the set. Six games to five does not, because the margin is one.
So at 6–5 play continues. Win the next game and it is 7–5 and the set is over. Lose it and the score is 6–6, which is where the tiebreak arrives.
6–0, 6–1, 6–2, 6–3, 6–4 → set over
6–5 → play on
7–5 → set over
6–6 → tiebreak
The tiebreak is a different game with different counting
At six games all, the ordinary game count is suspended and replaced by a single deciding game — the tiebreak. This is the point where the nesting becomes most visible, because the tiebreak abandons 15/30/40 entirely and counts in plain numbers: one, two, three.
The standard tiebreak goes to seven points, with a two-point margin. At 6–6 inside the tiebreak it continues until someone leads by two, which is why tiebreak scores of 9–7 or 15–13 appear. The player who wins it takes the set 7–6, and the tiebreak score is usually shown in brackets alongside.
Serving rotates unusually. One player serves the first point, then service alternates every two points, so that neither player gets a structural advantage from serving first. Players change ends every six points.
7–6 → the games in the set
(9–7) → the points in the tiebreak
The set was won by one game. That one game was the tiebreak, and it was won 9–7 on points because neither player could establish a two-point lead at 6–6.
The final set, and why it is not the same everywhere
The one part of tennis scoring that genuinely varies is the deciding set. Historically a final set could run indefinitely, because a tiebreak was not played — producing the celebrated marathon matches.
The major tournaments have converged on a longer tiebreak in the deciding set, played to ten points rather than seven, still with a two-point margin. That change was adopted at different times by different tournaments and the details have been revised more than once, so the deciding-set rule is the thing to check for the specific event you are watching rather than assume.
This is also why match length varies so much between formats. Men’s singles at the four majors is best of five sets; almost everything else, including women’s singles at the majors and most tour events, is best of three.
- Best of three — first to two sets. Most tour matches.
- Best of five — first to three sets. Men’s singles at the majors.
- Deciding set — commonly a ten-point tiebreak at 6–6, but confirm for the tournament.
What to listen for in the commentary
Most viewer confusion is a level-switching problem rather than a rules problem. The commentary says “40–30” and then “5–3” and then “two sets to love” within twenty seconds, and nothing announces that the scale changed three times.
- Words like love, 15, 30, 40, deuce, advantage — you are inside a single game.
- Small numbers up to about seven — games within the current set.
- “Sets to” — the match level.
- Plain counting past 7 with no 15/30/40 — you are in a tiebreak.
- “Break point” — the player receiving is one point from winning a game their opponent served. That is the pivot the whole nested structure is built to create.
What this page does not settle
This describes the scoring system as the governing rules set it out. Two things are deliberately not asserted.
The origin of 15, 30 and 40 is not settled, and the clock-face story is an explanation rather than a documented fact. And the deciding-set format is the one rule that differs by tournament and has changed repeatedly — check the event rather than relying on any general statement, including this one.