The ATP Rankings are the merit-based method used by the Association of Tennis Professionals (ATP) for determining the qualification for entry as well as the seeding of players in all singles and doubles tournaments. The first rankings for singles were published on 23 August 1973 while the doubles players were ranked for the first time on 1 March 1976. Ranking points are awarded according to the stage of tournament reached, and the prestige of the tournament, with the four Grand Slam tournaments awarding the most points. The rankings are updated every Monday, and points are dropped 52 weeks after being awarded (with the exception of the ATP Finals, from which points are dropped on the Monday following the last ATP Tour event of the following year). Novak Djokovic is the current world No. 1.
The ATP began as the men's trade union in 1972, through the combined efforts of Jack Kramer, Cliff Drysdale, and Donald Dell, and rose to prominence when 81 of its members boycotted the 1973 Wimbledon Championships. Just two months later, in August, the ATP introduced its ranking system intended to objectify tournament entry criteria, which up to that point were controlled by national federations and tournament directors.
The ATP's new ranking system was quickly adopted by men's tennis. While virtually all ATP members were in favor of objectifying event participation, the system's first No. 1, Ilie Năstase, lamented that "everyone had a number hanging over them," fostering a more competitive and less collegial atmosphere among the players.
The original ATP ranking criteria, which were then regularly published weekly only from mid-1979 and persisted through the 1980s, were based on averaging each player's results, though the details were revised a number of times. Starting in 1990, in conjunction with the expansion of ATP purview as the new men's tour operator, the ranking criteria were replaced with a 'best of' system modeled after competitive downhill skiing. This 'best of' system originally used 14 events but expanded to 18 in 2000.
For a better result within the same tour type to be transposed one has to wait for the expiry of the first worse result from previous year. It only expires at the drop date of that tournament and only if the player reached a worse result or has not entered the current year.
Ranking points gained in a tournament are dropped 52 weeks later, with the exception of the ATP Finals, from which points are dropped on the Monday following the last ATP Tour event of the following year.
The Monte-Carlo Masters 1000 became optional in 2009, but if a player chooses to participate in it, its result is counted and his fourth-best result in an ATP 500 event is ignored (his three best ATP 500 results remain). From 2009 until 2015, if a player did not play enough ATP 500 events and did not have an ATP 250 or Challenger appearance with a better result, the Davis Cup was counted in the 500's table. The World Team Cup was also included before its cancellation in 2012.
For the Davis Cup, from 2009 until 2015, points were distributed for the World Group countries. Instead of having an exact drop date they were gradually updated at each phase of the competition, comparing the player's results with his results from the previous year. E.g. if a player played two matches in a semifinal but plays one the next year only that one missing match will be extracted from his points).
A player who is out of competition for 30 or more days, due to a verified injury, will not receive any penalty. The ATP Finals will count as an additional 19th tournament in the ranking of its eight qualifiers at season's end.
For every Grand Slam tournament or mandatory ATP Tour Masters 1000 tournament for which a player is not in the main draw, and was not (and, in the case of a Grand Slam tournament, would not have been, had he and all other players entered) a main draw direct acceptance on the original acceptance list, and never became a main draw direct acceptance, the number of his results from all other eligible tournaments in the ranking period that count for his ranking is increased by one.
Once a player is accepted in the main draw of a Grand Slam tournament or ATP Tour Masters 1000 tournament,[c] his result in this tournament counts for his ranking, regardless of whether he participates. A player's withdrawal from an ATP Tour 500 event, regardless of whether the withdrawal was on time, results in a zero point included as one of his best of four results. Further non-consecutive withdrawals results in a zero point allocation replacing the next best positive result for each additional withdrawal.
Players with multiple consecutive withdrawals who are out of competition for 30 days or longer because of injury are not subject to a ranking penalty as long as verified and approved medical forms are provided; or, a player will not have the ranking penalty imposed if he completes the Promotional Activities requirement as specified under "Repeal of Withdrawal Fines and/or Penalties" or if the on-site withdrawal procedures apply. Players may also appeal withdrawal penalties to a Tribunal who will determine whether the penalties are affirmed or set aside.
Between 2000 and 2012, ranking points were awarded based on results in the Summer Olympics. This was changed before the 2016 Olympics where no ranking points were awarded.
With these rules, a player playing and winning the mandatory 4 Grand Slams and 8 ATP Masters 1000 events, a further 5 ATP 500 events and the Monte-Carlo Masters 1000 can amass a total of 19,500 points before the ATP Finals and end the calendar year with a maximum of 21,000 points. As of 2021[update], the maximum points achieved by any player is 16,950 by Novak Djokovic, on June 6, 2016.
(ATP 1000 series) Qualifying points changes to 12 points only if the main draw is larger than 56.
(ATP 500 series) Qualifying points changes to 10 points only if the main draw is larger than 32
(ATP 250 series) Qualifying points changes to 5 points only if the main draw is larger than 32
Players who draw a bye in the first round in the ATP 1000 series and lose their first match in the second round are considered to have lost their first round and receive the points equivalent to first round loss. Similarly, loss in the second round of the ATP 500 series and the ATP 250 series after drawing bye in first round will result in 0 points being awarded.
In addition qualifiers and main draw entry players will then also receive the points in brackets for the rounds they reached.
Starting in 2016, points were no longer awarded for Davis Cup ties, nor for the tennis tournament at the Summer Olympics.
Novak Djokovic holds the record for most weeks spent as world No. 1, as well as the ATP all-time record of seven year-end No. 1 rankings. He has the record of 16,950 ranking points, the most points ever held by any player.
Note: Not all year-end rankings listed were taken from the 31st of December. Due to the Australian Open's date in the 1970s through to the mid 1980s, the year-end ranking in 1974, 1978-1984 were recorded from varying dates.
^In weeks where there are not four Grand Slam tournaments and eight Masters 1000 tournaments in the ranking period, the number of a player's best results from all eligible tournaments in the ranking period will be adjusted accordingly.
^At least one of these tournaments must follow the US Open.
^"Accepted" means a direct acceptance, a qualifier, a special exempt, or a lucky loser, or having accepted a wild card.
^Kevin Curren became a naturalized American citizen in 1985 after representing South Africa.
^Ivan Lendl became a naturalized American citizen in 1992 after representing Czechoslovakia.