Calendar-year Grand Slam or Calendar Grand Slam is the achievement when a tennis player manages to win all the four major championships in the same calendar year. The four major championships are the Australian Open, French Open, Wimbledon and US Open. While winning all four majors consecutively but not within the same calendar year is called non-calendar year Grand Slam, winning the four majors at any point during the career is known as a career Grand Slam.

The Grand Slams, also known as majors, are the tournaments that offer the most ranking points, prize money. The Slams are overseen by the International Tennis Federation (ITF), rather than the separate men and women’s tour organising bodies. While the men’s tour organising body is called the Association of Tennis Professionals (ATP), the women’s organising body is called the Women’s Tennis Association (WTA). However, both the ATP and WTA give ranking points based on players’ performances in the tournaments.

The Australian Open is held in January, the French Open is held in May-June. Wimbledon is played at the SW19 from late June to early July. As for the US Open, it is held in the August-September period.

While the Australian Open and the US Open are played on hard court, the Roland Garros is played on the clay court and the Wimbledon on grass.

The most elite of them all, Wimbledon, is the oldest tournament – founded in 1877. The US Open was founded in 1881, the French Open in 1891, and the Australian in 1905. However, the tournaments got their official designation as majors in 1923.

Players to win a calendar Grand Slam:

1. Don Budge (men’s singles, 1938)

2. Maureen Connolly (women’s singles, 1953)

3. Rod Laver (men’s singles, 1962 and 1969)

4. Margaret Court (women’s singles 1970)

5. Steffi Graf (women’s singles 1988)

Players to win a non-calendar Grand Slam

1. Martina Navratilova (women’s singles 1984)

2. Steffi Graf (women’s singles 1994)

3. Serena Williams (women’s singles, 2003 and 2005)

4. Novak Djokovic (men’s singles, 2016)