Tennis Rules and Scoring: Why 15, 30, 40 — and What Changed in 2022

The scoring, plainly

Points won	Called
0	Love
1	15
2	30
3	40
4	Game — if two clear

At 40-40 the score is deuce, and the game cannot be won by a single point. A player must take two in a row: the first gives them advantage, the second the game. Lose the next point at advantage and the score returns to deuce, however many times that takes.

A set goes to the first to six games with a two-game margin. At 6-6, a tiebreak — first to seven points, two clear, counted in ordinary numbers.

A match is best of three sets, or best of five in men’s Grand Slam singles.

Nobody knows why it is 15, 30, 40

This is the most-asked question about tennis and it has no reliable answer.

The explanation you will find nearly everywhere is a clock face: quarter-hours at 15, 30, 45, with 45 worn down to 40 in speech. It is tidy, and there is no contemporaneous evidence for it. The theory appears long after the scoring was already in use.

The same is true of love for zero. The popular derivation is the French l’œuf — an egg, for the shape of a nought, the same logic that gives cricket its duck. The competing account is the English phrase playing for love, meaning playing for nothing. Neither is documented at the point the word entered the sport.

An honest page says so. Tennis inherited its scoring from a game older than its own records, and the explanations circulating are reconstructions rather than history — the same pattern that surrounds when football was actually established.

The disagreement that lasted decades

Here is the part of tennis’s rulebook that genuinely deserves attention, and it is barely covered.

The tiebreak solved the problem of endless sets — except in the deciding set, where the four Grand Slams could not agree. As recently as the 2021 season:

Tournament	Final-set rule before 2022
Australian Open	10-point tiebreak at 6-6
US Open	7-point tiebreak at 6-6
Wimbledon	7-point tiebreak at 12-12
Roland Garros	No tiebreak — play on until two games clear

Four tournaments at the summit of the same sport, ending the same situation four different ways. A match that would have been decided by a tiebreak in New York could still be going in Paris.

Wimbledon’s 12-12 rule was itself a recent concession, introduced in 2019 after matches that ran past reasonable limits. Roland Garros held out entirely.

March 2022: they finally agreed

On 16 March 2022, the four Grand Slam tournaments jointly announced a single rule, first used at Roland Garros that year.

At six games all in the deciding set: a ten-point tiebreak, won by two clear points.

It is worth registering how unusual that announcement was. These are four independent tournaments, in four countries, under different national federations, each with its own traditions and commercial interests. Nothing compelled them to align. They did it because the inconsistency had become indefensible to explain.

That is a rarer outcome than it sounds. Most sports resolve this kind of split by having one body impose a rule; tennis reached it by four sovereign tournaments choosing to converge. Compare football, where a single body writes the laws for everyone, or gymnastics, where the FIG’s writ runs everywhere.

The tiebreak, in detail

In a set, at 6-6: first to seven, two clear.

In a deciding set at a major, at 6-6: first to ten, two clear.

Both work the same way otherwise. The player due to serve serves one point; thereafter service alternates every two points, and ends change every six points. Because the tiebreak must be won by two, it has no upper bound — the sport removed the endless set but did not quite remove the endless point sequence.

Serving is its own rulebook

Service has more law attached to it than any other part of tennis: foot faults, lets, the two-serve allowance, and which side of the centre mark you must stand on.

That is covered separately in the rules of serving in tennis.

What the ITF actually governs

The International Tennis Federation publishes the Rules of Tennis, and they cover far more than scoring — ball specifications, court dimensions, racket limits, and the conduct of a let.

But the Grand Slams are not ITF events. They are run by their own national associations under the Grand Slam Board, which is exactly why the final-set rule could differ between them for so long, and why fixing it required agreement rather than instruction.

More on the tournaments themselves is in Grand Slam women’s singles champions, and more rules coverage in rules and techniques.