The ATP has used a computerized system for determining the rankings since August 23, 1973.
[2] Starting in 1979, an updated rankings list is released at the beginning of each week.
As of 2019, the rankings are calculated by totaling the points a player wins in his best eighteen tournaments, subject to certain restrictions.
[9] 2022–2023; Normal ATP’s ranking system over a 52-week period restored since August 2021.
[10] 2024–present; An updated ATP Rankings breakdown with increase in points at tour-level events since January 2024.
1 finishes, achieving the feat for eight years (including the two pandemic-impacted seasons[15]).
[22] Federer is the player with the longest time span (14 years) between his first and most recent dates at No.
1 (February 2004–June 2018),[23] while Rafael Nadal is the only player to hold the top ranking in three different decades, spanning 11 years and 5 months (2008–2020).
1 on February 21, 1983, but did not win his first Grand Slam title until the 1984 French Open.
1 on March 30, 1998, but retired without ever having won a Grand Slam title, making him the only No.
Since 1973 when the ATP rankings started, there have been 13 years in which one player held the top spot for the entire year: Jimmy Connors in 1975, 1976, and 1978; Lendl in 1986 and 1987; Pete Sampras in 1994 and 1997; Hewitt in 2002; Federer in 2005, 2006, and 2007; and Djokovic in 2015 and 2021.
1 ranking (the most in any single year): Sampras, Carlos Moyá, Yevgeny Kafelnikov, Andre Agassi, and Patrick Rafter.
The statistics are updated only when the ATP website revises its rankings (usually on Monday mornings except when tournament finals are postponed).
Prior to the early 1990s this was not always the case, in some instances the "ATP Player of the Year" and the Year-end No.
Ten of them have achieved this more than once, of which four (Lendl, Federer, Djokovic, Nadal) have done so in non-consecutive years.